ECONOMIC EVALUATION OF HATCHABILITY AND EFFECT OF …prr.hec.gov.pk/jspui/bitstream/123456789/7623/1/Javed iqbal Poultry... full pdf.pdfDay-old Chick 2.4.6 Spiking 2.4.7 Comparison

1

ECONOMIC EVALUATION OF HATCHABILITY AND

EFFECT

OF BROILER BREEDER AGE AND EGG WEIGHT ON

HATCHABILITY, CHICK QUALITY AND BROILER

PRODUCTION

JAVID IQBAL

06-arid-264

Department of Poultry Science

Faculty of Veterinary and Animal Sciences

Pir Mehr Ali Shah

Arid Agriculture University Rawalpindi

Pakist

an

2015

ECO

NO

MIC

EVA

2

LUA

TIO

N

OF

HAT

CHA

BILI

TY

AND

EFF

ECT

OF BROILER BREEDER AGE AND EGG WEIGHT ON

HATCHABILITY, CHICK QUALITY AND BROILER

PRODUCTION

by

JAVID IQBAL (06-arid-264)

A dissertation submitted in partial fulfillment of the

requirements for the degree of

Doctor of

Philos

ophy

in

Poult

ry

3

Scien

ce

Department of Poultry Science Faculty of Veterinary and Animal Sciences

Pir Mehr Ali Shah Arid Agriculture University Rawalpindi Pakistan

2015

CERTIFICATION

I hereby undertake that this research is an original one and no part of

this thesis fall under plagiarism. If found otherwise, I will be responsible for

the consequences.

Student Name: Javid Iqbal Signature: _________________

Registration Number: 06-arid -264 Date:

_____________________

Certified that the contents and the form of the thesis entitled

“Economic Evaluation of Hatchability and Effect of Broiler Breeder

Age and Egg Weight on Hatchability, Chick Quality and Broiler

Production” submitted by Mr.

Javid Iqbal have been found satisfactory for the requirement of the

degree.

Supervisor: _______________________________

(Dr. Nasir Mukhtar)

Co Supervisor:

_______________________________

(Dr. Sohail Hassan Khan)

4

PRI, Rawalpindi

Member: _______________________________

(Dr. Tanveer

Ahmad)

Member: _______________________________

(Dr. Riaz Hussain)

Chairperson: ____________________________________

Dean FV & AS: __________________________________

Director Advance Studies: __________________________________

5

6

DEDICATED TO MY LOVING

PARENTS & MY CHILDREN

CONTENTS

Page

List of Tables 13

List of Figures 17

List of Acronyms 18

Acknowledgement 20

ABSTRACT 23

1 GENERAL INTRODUCTION 1

2 EPIDEMIOLOGICAL EVALUATION OF ECONOMICS OF 4

HATCHABILITY IN BROILER BREEDER

2.1 INTRODUCTION 4

7

2.2 REVIEW OF LITERATURE 6

2.3 MATERALS AND METHODS 8

2.3.1 Epidemiological Evaluation of Economics of Hatchability in 8

Broiler Breeders

2.3.1.1 Egg Production 9

2.3.1.2 Hatchable Egg Percentage 9

2. 3.1.3 Egg Weight 10

2 3.1.4 Egg Hatchability 10

2 3.1.5 Hen Housed Eggs 10

2 3.1.6 Hen Housed Hatchable Eggs 10

2. 3.1.7 Number of Chicks Produced per Hen Housed 11

2 3.1.8 Feed Consumption per Hatching Egg 11

2. 3.1.9 Feed Consumption per One Day-old Chick 11

2. 3.1.10 Male and Female Body Weights 12

2 3.1.11 Spiking 12

2.3.2 Data Analysis 12

2.4 RESULTS AND DISCUSSION 13

2.4.1 Egg Production, Hatchable Egg Percentage, Hen Housed 13

Eggs and Hen Housed Hatching Eggs

2.4.2 Male and Female Body Weight

16

8

2.4.3 Egg Weight

2.4.4 Egg Hatchability and Number of Chicks Produced per Hen

Housed

2.4.5 Feed Consumption per Hatching Egg and to Produced One

Day-old Chick

2.4.6 Spiking

2.4.7 Comparison of Production Performance with Strain Standard

2.4.8 Annual Effect of Hatchability (Day-old chick /hen house) on

Feed consumption and Feed Cost

24

26

32

36

36

38

3 EFFECTS OF EGG SIZE (WEIGHT) AND AGE ON EGG

QUALITY CHARACTERISTICS OF BROILER BREEDER

41

3.1 INTRODUCTION 41

3.2 REVIEW OF LITERATURE

44

3.2.1 Effect of Egg weight (Size) and Age of Broiler Breeder on Egg

Quality Characteristics

44

3.3 MATERIALS AND METHODS 48

3.3.1 Selection of Birds and Experimental Site 48

3.3.2 Collection and Selection of Eggs 48

3.3.3 Measured Egg Quality Parameters 49

3.3.3.1 Egg Weight 49

3.3.3.2 Shell Weight

49

3.3.3.3 Shell Thickness

49

3.3.3.4 Yolk Weight 49

3.3.3.5 Albumen Weight 52

3.3.3.6 Yolk to Albumen Ratio 52

3.3.3.7 Shape Index 52

3.3.3.8 Egg Specific Gravity 52

9

3.3.4 Statistical Analysis 53


3.4.1 Influence of Egg Size on Egg Quality Characteristics 53

3.4.2 Influence of Age on Egg Quality Characteristics 60

4 EFFECTS OF EGG SIZE (WEIGHT) AND AGE ON HATCHING

PERFORMANCE AND CHICK QUALITY OF

BROILER BREEDER

66

4.1 INTRODUCTION 66


4.2.1 Hatchability

4.2.2 Effect of Egg Size (Weight) of Broiler Breeder on

Hatchability

4.2.3 Effect of Age of Broiler Breeder on Hatchability

4.2.4 Effect of Egg Size (Weight) and Age of Broiler Breeder on

Egg Weight Loss Percentages during Incubation


Embryo Death during Incubation and Pipped-not-Hatched

Egg


Chick Yield (Chick to Egg weight Ratio)

4.2.7 Effect of Egg Size (Weight) and Broiler Breeder Age on Chick Quality of Broiler

68

68

68

70

72

75

78

80

4.3 MATERIALS AND METHODS

83

4.3.1 Selection of Birds and Experimental Site 83

4.3.2 Collection and Storage of Eggs 83

10

4.3.3 Incubation and Hatching Conditions

4.3.4 Measured Egg Weight Loss during Incubation

4.3.5 Measured Breakout Analysis (Fertility, Hatchability of Set

and Fertile eggs, Embryonic Mortality, Infertile Eggs, Pipped-

not-Hatched Eggs and Culled Chicks)

4.3.6 Measured Hatch Percentage

4.3.7 Measured Chick Weight

4.3.8 Measured Chick Yield

4.3.9 Measured Chick Length

4.3.10 Statistical Analysis

84

84

85

86

86

86

86

87


4.4.1 Effect of Hatching Egg Size on Egg Weight Loss in Hubbard

Classic Broiler Breeder at Early, Mid and Late Stage of

Production Period

4.4.2 Effect of Broiler Breeder Age on Egg Weight Loss During

Incubation

87

93

4.4.3 Effect of Hatching Egg Size on Hatchability Traits in

Hubbard 96

Classic Broiler Breeder at Early, Mid and Late Stage of

Production Period

4.4.4 Effect of Broiler Breeder Age on Fertility and Hatchability

Traits

4.4.5 Influence of Egg Size on Chick Quality in Hubbard Broiler

Breeder at Early, Mid and Late Stage of Production Period

4.4.6 Effect of Broiler Breeder Age on Chick Quality

106

110

117

5 EFFECTS OF EGG SIZE (WEIGHT) AND AGE ON POST

HATCHING PERFORMANCE OF BROILER BREEDER

121

5.1 INTRODUCTION

121

5.2 REVIEW OF LITERATURE 123

11

5.2.1 Effects of Egg Weight of Broiler Breeder on Broiler

production Parameters (Feed Intake, Live Body Weights and

Feed Conversion Ratio)

5.2.2 Effects of Age of Broiler Breeder on Broiler Production

Parameters (Feed Intake, Live Body Weights and Feed

Conversion Ratio)

5.2.3 Effects of Egg Weight and Age of Broiler Breeder on Broiler

Mortality

123

127

129

5.3 MATERIALS AND METHODS 131

5.3.1 Selection of Day-old Chicks, Experimental Site and

Rearing Conditions

131

5.3.2 Measured Parameters 132

5.3.2.1 Day-old Chick’s Weight 132

5.3.2.2 Body Weight 137

5.3.2.3 Feed Consumption 137

5.3.2.4 Feed Conversion Ratio 137

5.3.2.5 Mortality


138

138


5.4.1 Effect of Hatching Egg Size on Post-Hatch Chick Growth

5.4.2 Effect of Breeder Age on Post-Hatch Chick Growth

5.4.3 Effect of Hatching Egg Size on Broiler Feed Intake

5.4.4 Effect of Breeder Age on Broiler Feed Intake

5.4.5 Effect of Hatching Egg Size on Broiler Feed Conversion

Ratio

5.4.6 Effect of Breeder Age on Broiler Feed Conversion Ratio

5.4.7 Effect of Breeder Hatching Egg Size on Mortality in Broiler

138

146

148

153

155

160

163

12

5.4.8 Effect of Breeder Age on Mortality in Broiler

167

6 GENERAL DISCUSSION

SUMMARY

CONCLUSION

170

182

190

LITERATURE CITED 191

13

LIST OF TABLES

Table No. Page

2.1 Performa for broiler breeder performance record 15

2.2 Flocks with maximum and minimum number of day-old chicks 23 per hen

housed

2.3 Hatchability of flocks with maximum and minimum average egg

27 weight

2.4 Comparisons of the average performance of broiler breeder with 39 that of

strain standards

2.5 Effect of day-old chick /hen housed (hatchability) on feed 40 consumption

and feed cost

3.1 Composition of broiler breeder layer diet (30, 45 and 60 weeks) 50

3.2 The plan to study the effect egg weight and age on egg quality 51

parameters in broiler breeder

3.3 Effect of egg size on egg quality characteristics in hubbard broiler 55

breeder at early (30 week) stage of production period


breeder at mid (45 week) stage of production period

14


breeder at late (60 week) stage of production period

3.6 Effect of age on egg quality characteristics in hubbard broiler 61

breeder

4.1 Effect of egg size on egg weight loss in hubbard classic broiler 90 breeder

at early (30 week) stage of production period

4.2 Effect of egg size on egg weight loss in hubbard classic broiler 91 breeder

at mid (45 week) stage of production period

4.3 Effect of egg size on egg weight loss in hubbard classic broiler 92


4.4 Effect of age on egg weight loss in broiler breeder 94

4.5 Effect of egg size on fertility and hatchability parameters in 100

hubbard classic broiler breeder at early (30 week) stage of production period


hubbard classic broiler breeder at mid (45 week) stage of production period


hubbard classic broiler breeder at late (60 week) stage of production period

4.8 Effect of broiler breeder age on fertility and hatchability traits 109

15

4.9 Effect of egg size on chick quality in hubbard classic broiler 112

breeder at early (30 week) stage of production period


breeder at mid (45 week) stage of production period



4.12 Effect of broiler breeder age on chick quality 120

5.1 Composition of broiler starter diet 133

5.2 Composition of broiler grower diet 134

5.3 Composition of broiler finisher diet 135

5.4 The plan to study the effect of egg weight, age and broiler sex on 136

broiler production parameters

5.5 Effect of broiler breeder egg size on post-hatch broiler chick 141

weight at early (30 week) stage of production period


weight at mid (45 week) stage of production period


weight at late (60 week) stage of production period

5.8 Effect of breeder age on broiler live body weight 147

16

5.9 Effect of broiler breeder egg size on broiler feed intake at early 150

(30week) stage of production period

5.10 Effect of broiler breeder egg size on broiler feed intake at mid 151


5.11 Effect of broiler breeder egg size on broiler feed intake at late 152


5.12 Effect of breeder age on broiler feed intake 154

5.13 Effect of broiler breeder egg size on broiler feed conversion ratio 157

at early (30 week) stage of production period

5.14 Effect of broiler breeder egg size on broiler feed conversion ratio

158

at mid (45 week) stage of production period

5.15 Effect of broiler breeder egg size on broiler feed conversion ratio 159

at late (60 week) stage of production period

5.16 Effect of breeder age on broiler feed conversion ratio 161

5.17 Effect of broiler breeder egg size on broiler mortality at early (30 164

week) stage of production period

5.18 Effect of broiler breeder egg size on broiler mortality at mid 165


5.19 Effect of broiler breeder egg size on broiler mortality at late 166


17

5.20 Effect of breeder age on broiler mortality 169

LIST OF FIGURES

Fig. No. Page

2.1 Trend-cycle of egg production in broiler breeders depending on

17 weeks of age

2.2 Trend-cycle of hatching egg (%) in broiler breeders depending

18 on weeks of age

2.3 Trend-cycle of hen housed eggs in broiler breeders depending

19 on weeks of age

2.4 Trend-cycle of hen housed hatching eggs in broiler breeders

20 depending on weeks of age

2.5 Trend of male and female body weights in broiler breeder 22

depending on weeks of age

2.6 Trend-cycle of egg weight in broiler breeders depending on

25 weeks of age

2.7 Trend-cycle of egg hatchability in broiler breeders depending on

29 weeks of age

2.8 Trend-cycle of number of chicks per hen housed in broiler 30

breeders depending on weeks of age

18

2.9 Correlation between hatchability and number of chicks per hen

31 housed in broiler breeder.

2.10 Trend-cycle of feed consumption (g) per hatching egg in broiler

33 breeders depending on weeks of age

2.11 Trend-cycle of feed consumption (g) per day-old chick in broiler

34 breeders depending on weeks of age

2.12 Correlation between numbers of chicks per hen housed and feed

35 Consumption per day-old chicks in broiler breeder.

2.13 Trend of male spiking percentage in broiler breeder depending

37 on weeks of age

LIST OF ACRONYMS

Ca

CF

CP

cm

cm3

°C

d

EWL

Calcium

Crude fiber

Crude protein

Centimeter

Cubic centimeter

Centigrade (unit of measuring temperature)

days

Egg Weight Loss

19

FCR Feed Conversion Ratio

FM

G

Female

Gram

g/E

h

Gram per egg

Hour

HH Hen housed

HE/HH

HWE

IB

IBD

IU

Hatching eggs per hen house

Heavy weight egg

Infectious Bronchitis

Infectious Bursal Disease

International Unit

kg Kilogram

K Cal/kg Kilo Calories per Kilogram

LWE

Low weight egg

ME Metabolizable Energy

M Male

20

Min. Minimum

Max. Maximum

mm

MWE

ND

No.

Millimeter

Medium weight egg

Newcastle Disease

Number

PPA

Pcs

Pakistan Poultry Association

pieces

PRI Poultry Research Institute

%

RH

Percentage

Relative Humidity

Rs

SG

Rupees

Specific gravity

Wt. Weight

wk week

wks Weeks

et al And others

♂ Male

♀ Female

ACKNOWLEDGEMENT

21

I am thankful to most gracious, ALMIGHTY ALLAH, who gave me

the health and opportunity to complete this work. I bow before my

compassionate

endowments, Peace be upon him HOLY PROPHET MUHAMMAD

(PBUH),

who is ever an ember of guidance and knowledge for humanity.

I deem it utmost pleasure to avail this opportunity to express the

heartiest gratitude and deep senses of obligation to my kind supervisor Dr Nasir

Mukhtar,

Assistant Professor, Department of Poultry Science PMAS-Arid

Agriculture University Rawalpindi. His skillful guidance, unfailing patience,

mastery advice and inspiring attitude made it very easy to undertake this work

and to write manuscript.

I have the honor to express my deep sense of gratitude and profound

indebtedness to Prof. Dr. Safder Anjum, Dean Faculty of Veterinary and

Animal Sciences PMAS Arid Agriculture University Rawalpindi, for his

untiring help at all times.

I deem it my utmost pleasure in expressing my gratitude with the

profound benedictions to Co-Supervisor Dr. Sohail Hassan Khan, Assistant

Director, Poultry Research Institute, Rawalpindi, for his time and

cooperation, which facilitated me with every possible way. Thanks are also

extended to other committee members Dr. Tanveer Ahmad, Associate

Professor, Department of Animal Nutrition, Faculty of Veterinary and

Animal Sciences PMAS Arid

22

Agriculture University Rawalpindi and Dr. Riaz Hussain , Assistant

Professor, Department of Anatomy, Faculty of Veterinary and Animal Sciences

PMAS, Arid Agriculture University, Rawalpindi, for their cooperation.

I like to acknowledge my sincere thanks to my friends, Dr. Asghar Ali

Mian, Retired professor of poultry, Dr. Mansoor Abdullah, Associate

Professor,

Department of Animal physiology, Faculty of Veterinary and Animal

Sciences

PMAS, Arid Agriculture University Rawalpindi, Dr. Zaib-ur-

Rehman, Lecturer, Department of Poultry Science, Faculty of Veterinary and

Animal Sciences PMAS,

Arid Agriculture University Rawalpindi, Dr. Gulrez Ahmad, Chief

Nutritionist in

Sadiq Feeds (Pvt.) Ltd. and Dr. Naem Tariq, National Technical

Consultant Hubbard, their encouragement and valuable suggestions.

Words cannot express the feelings of my love devotion, thanks and

gratitude to my wife and sweet children. My success is really the fruit of

sincerest prayers of my parents and family members. Tributes are due to my

parents, by whom I was always inspired and encouraged for my studies. I

submit my earnest thanks to all of them for their encouragement and moral

support which made this possible. May Allah bless them to the virtues.

(JAVID IQBAL)

23

ABSTRACT

This study was divided into four phases. The main objective of the

first phase of study was to evaluate the performance of broiler breeders. For

this purpose, a complete production data of 20 Hubbard Classic broiler

breeder flocks from 26 to 60 weeks of age was collected at random for the

years 2005 to 2011. The average percentages of egg production, hatchable

eggs, egg weight and egg hatchability was found as 65.7%, 96.3%, 64.7 g

and 79.3%, respectively during production period. At 60 week of age,

average egg weight, hen housed eggs, hen housed hatchable eggs and number

of chicks produced per hen housed were 69.8 g, 149.8, 145.1 and 119.10,

respectively. Feed consumptions per hatchable egg and day-old chick were

395 and 486 g, respectively. Male and female body weights at 60 week were

observed as 4785 and 3929 g, respectively. Only 30% flocks were spiked

during production cycle. Spiking of young males with aged males was started

from 41 week and continued to 55 week. The average production

performances differed significantly (p≤0.05) with strain standards and most

of production parameters were below the strain standards. It was also

observed that a strong positive correlation (r2 =0.980) between hatchability

and number of chicks produced per hen housed, and a strong negative

correlation (r2 = -0.833) between the number of chicks produced per hen

housed and feed consumed to produce one day-old chick per hen housed exist

in broiler breeders. Generally, it was observed that poultry breeders who,

followed poor management practices, resulted in low numbers (119.1) of

day-old chicks per hen house than strain standard (139).

24

In second phase, the objective was to study the effect of egg size and

age on egg quality traits during early (30wk), mid (45wk) and late (60wk) stages

of production period in broiler breeder. A commercial broiler breeder flock of

Hubbard Classic strain (25 week old) was selected for study. A total

of 2000 Hubbard Classic females and 180 males (male to female ratio 1: 11)

were selected and reared in the poultry house. During 4-8 hour of light

periods, a total of 930 hatchable eggs were selected at the early, mid and late

stage of production period and equally distributed into 3 egg-sized categories

(small, medium and large). Ten (10) eggs from each egg category were

analyzed for the egg quality parameters within 24 hours of laying. At an early

stage of production period, the results revealed that yolk weight augmented

(p≤0.05) with increase of egg size but all other egg quality parameters (shell

weight, shell thickness, albumen weight, yolk to albumen ratio, shape index

and specific gravity) were not influenced (p≥0.05) by egg size. At mid stage

of production period, shell weight, shape index and specific gravity were

reduced (p≤0.05) with increase in egg size and shell thickness, yolk weight,

albumen weight and yolk to albumen ratio were not influenced (p≥0.05) by

egg size. At late stage of production cycle, shell weight, shell thickness, shape

index and specific gravity were reduced (p≤0.05) with increase of egg size

and yolk weight, albumen weight and yolk to albumen ratio were not

influenced (p≥0.05) by egg size. The egg weight increased (p≤0.05) with age.

Yolk weight and yolk to albumen ratio were improved (p≤0.05) while shell

thickness, albumen weight, shape index and specific gravity were reduced

(p≤0.05) with advancing of broiler breeder age.

In third phase, the objective was to study the effects of egg size

(small, medium and large) and flock ages (30, 45 and 60 wks) on hatchability

25

and chick quality traits. A total of 300 hatchable eggs from each egg category

were selected at early, mid and late stage of production period. These eggs

were shifted to broiler hatchery and stored at 20 oC and 75% relative humidity

for 3 days prior to incubation. The results showed that egg weight loss

percentage decreased (p≤0.05) with increase of egg size at all stages of

production period, and advancing age of breeder hen. Fertility and

hatchability parameters were influenced (p≤0.05) by egg size and age. The

best combination of fertility and hatchability values were recorded in

medium-sized eggs (60-69g) and at mid stage of production period.

Maximum (p≤0.05) embryonic deaths during incubation and higher

percentage (p≤0.05) of infertile eggs were observed in small-sized eggs

(<51g) and extralarge-sized eggs (>70g) but the embryonic deaths were not

influenced (p≥0.05) by age of breeder hen. Maximum (p≤0.05) infertile eggs,

pipped-not-hatched eggs and culled chicks were recorded in older (60wk) as

compared to younger (30, 45wk) broiler breeders. Chick weight and chick

length were amplified (p≤0.05) with increase of egg size at all stages and

chick yield at late stage of production period.

Chick weight and chick length were improved (p≤0.05), however chick

yield was not influenced (p≥0.05) by age of breeder hen.

In fourth phase, the objective was to determine the effect of broiler

breeder egg size and age on post-hatching performance of broiler chicks. A total

of

90 day-old chicks (45♂ and 45♀) from each egg-sized category were

reared for 5 weeks at early, mid and late stage of production period. The

results showed that live body weight of both sex of broiler improved (p≤0.05)

with increasing the egg size during the first 3 week and become insignificant

26

(p≥0.05) from 4th week of age at all stages of production cycle. Similarly, the

chick growth improved (p≤0.05) during first 2 week with age of breeder hen.

However, the influence of age on chick growth from 3rd to 5th weeks was

non-significant (p≥0.05). At 3rd week of broiler age, feed intake of broiler

(both sex) at early stage, feed intake of female at mid stage and feed intake

of male at late stage of production period increased significantly (p≤0.05)

with increasing in egg size. However, influence of egg size on broiler (both

sex) feed intake during first, second, fourth and fifth week of growing period

was non-significant (p≥0.05). Breeder age had non-significant (p≥0.05)

effect on broiler feed intake from 1st to 5th weeks of age. Generally, egg size

had non-significant (p≥0.05) effect on broiler FCR. However, female broiler

FCR significantly (p≤0.05) improved with increasing of egg size

during 2nd and 3rd week of growth period at early and late stage of production

period. Broiler chicks (regardless sex) hatched from 45 week old breeder had

efficient FCR at 5th week than broiler from younger (30wk) or older (60wk)

breeders. Egg size at different stages of production cycle, and breeder age

had non-significant (p≥0.05) effect on mortality of broiler chicks, reared from

1st to 5th weeks of age.

27

Chapter 1

GENERAL INTRODUCTION

Poultry industry, with its fast growth rate 8-10 percent annually, is the second

largest industry of Pakistan (Mukhtar et al., 2012) and playing a pivotal role in

supplying animal protein (eggs and meat) for the fast growing human population in

the country (ESP, 2013-14). Optimization of egg and meat production can be

achieved through updated hatchery and breeder farm management regimens (Heier

and Jarp, 2001). The hatchery has a prime importance in the broiler production

chain. The successful hatchery operations are monitored by good hatchability

percentage and number of saleable good quality healthy chicks (Yassin et al., 2008).

Hatchery factors that influence the hatchability of fertile eggs are the humidity,

temperature, ventilation, egg orientation and turning frequency (Elibol and Brake,

2006; Decuypere and Bruggeman, 2007).

The maximum fertility and hatchability percentage of parent flocks can be

achieved through best and healthy breeding males and females. Scoring the good

hatchability from fertile egg starts from the time of laying to the time it stays in egg

store room, incubator and hatcher. Improper egg handling during critical periods

particularly collection and storage or inefficient working of incubator may damage

the inherent ability of egg to produce a good quality chick. Besides the careful

management of fertile eggs, many other factors affect the hatchability of eggs such

as age of hen (Lapao et al., 1999), age of male (Bramwell et al., 1996), mating ratio

(Sainsbury, 1992), egg shell quality (Roque and Soares, 1994), frequency of egg

28

collection (Fasenko et al., 1991) and egg storage duration and conditions (Lapao et

al., 1999). Internal egg quality and optimum calcium

1

deposit in the shell of hatching eggs are affected by high environmental temperature

in poultry house (Mahmoud et al., 1996), viral diseases (Thear, 2005) and nutritional

values of hen diet (Sutcliffe and Boorman, 1998) resulted in low hatchability.

Egg size is another important factor which affects the hatchability of chicken

(Ng’ambi et al., 2013; Rashid et al., 2013). Ideal hatchability in broiler breeders is

achieved when egg weight ranges from 55-65 g (North and Bell, 1990). The egg size

influenced the proportions of contents of the hatching eggs (Traldi et al., 2011). The

physical quality of egg play an important role in the development of embryo and

successful hatching, consequently influencing the hatching results (Narushin and

Romanov, 2002). The most influential parameters are egg size, shape index, shell

thickness and quality of the egg contents. Similarly, low albumen quality (Tona et

al., 2004) and high cholesterol contents also affect the hatchability (Dikmen and

Sahan, 2007).

A good quality day-old chick is a crucial hinge between breeder farm and

hatchery that evaluates the economic efficiency of poultry production chain. The

quality of day-old chick affects the future broiler performance (Mendes et al., 2007;

Wolanski et al., 2007). Chick weight is the most commonly used to evaluate the

day-old chick quality (Deeming, 2000) and is an important predictor of final body

weight (Petek et al., 2010) followed by chick length (Hill, 2001; Molenar et al.,

2007; Mukhtar et al., 2013). The percentage of poor quality chicks was higher in

older (45 week) than in younger (35 week) flocks (Tona et al., 2004). Poor chick

quality was associated with larger than average sized eggs at a particular flock age

29

(Lawrence et al., 2004; Kumpula and Fasenko, 2004). Early chick mortality in

broiler results a loss in the economy of broiler farms and hatcheries and deficiency

in fruitful output of broiler breeder flocks. Chick mortality also affects the welfare

of broilers (European Union, 2007).

The time taken for a broiler to grow to market weight is decreasing with the

passage of time. In 1957, a broiler strain attained market weight of 1.4 kilogram in

84 days (Havenstein et al., 2003); it currently takes 40 days for a broiler to achieve

3 kilogram market live body weight (Leeson, 2012). Broiler production performance

is affected by a number of factors particularly age (Peebles et al., 1999), egg size

(Ulmer-Franco et al., 2010) and egg shell quality (Tona et al., 2004). Alabi et al.

(2012) and Ulmer-Franco et al. (2010) reported that chicks hatched from largesized

eggs had higher daily live weight gain than from small-sized eggs but feed

conversion ratio is not affected by egg size.

In Pakistan, no previous epidemiological study is carried out on hatchability

of broiler breeder’s eggs. Similarly, no reference exists that explain the effect of age

and egg size on hatching egg quality, fertility, hatchability, chick quality and

subsequent performance of broiler chicks. Thus the present study is planned with

following objectives:

• To appraise the broiler breeder’s production performance and economics of

hatchability through epidemiological study.

• To study the effect of broiler breeder age and egg size on hatching egg

quality characteristics, fertility, hatching performance, chick quality and

post-hatch broiler performance.

30

Chapter 2

EPIDEMIOLOGICAL EVALUATION OF ECONOMICS OF

HATCHABILITY IN BROILER BREEDER

2.1 INTRODUCTION

Hatchability is one of the most important economic performance

indicators for broiler hatching egg industry (Schaal and Cherian, 2007).

Hatchability means the number of day-old chicks hatched out of incubated eggs.

The production of best quality day-old chick depends upon the healthy breeding

and hatching performance of the broiler breeder flocks. Failure of egg to hatch is

mainly due to infertility or embryo death after laying of fertile egg (King’ori, 2011).

During most of the laying period, 90% fertility of eggs produced by broiler breeder

flocks is acceptable (Austic and Nesheim, 1990).

The maximum fertility and hatchability percentage of parent flocks can be

achieved through healthy breeding females and males having body weights very

close to strain standards weights throughout production period. Scoring the good

hatchability from fertile egg starts from the time, it is laid to the time it hatches out.

Any inaccurate condition provided to fertile eggs during collection, storage or

incubation may damage the inherent ability of egg to produce a good quality chick.

Besides the careful management of fertile eggs, many other factors affect the

hatchability of eggs such as age of flock, time of egg storage, egg storage conditions

and egg shell quality (Peebles and Brake, 1987; Lapao et al., 1999; Roque and

Soares, 1994; Tona et al., 2007).

4

31

Female fertility can affect the number of chicks hatched as unfertile eggs (do

not produce chicks). An excessive intake of nutrients resulted in obese hen that

decreased fertility due to a decrease in hen ability to store and transport sperm cells

as a consequence of fat blockage of storage tubules (McDaniel et al., 1981).

Efficiency of broiler production depends on the quality of the day-old chick

(Mendes et al., 2007; Wolanski et al., 2007; Mukhtar et al., 2013). Early chick

mortalities during the broiler production results in the economic loss of broiler

farms and hatcheries and deficiency in fruitful output of broiler breeder flocks.

Early chick mortality also influences the welfare of broilers (European Union,

2007).

The production cost of day-old chick has prime importance in poultry

production. Feed cost has a major role in the production of a day-old chick. The

cost of feed is increasing day by day due to shortage of feed ingredients because of

their increasing demands for rapidly growing poultry industry. Various types of

cereals (e.g. Maize, wheat and rice etc.) are major part of poultry feed. Increasing

demands of these cereals for poultry industry are inserting pressure for their

availability to human foods. So, it is imperative to maximize the fruitful utilization

of poultry feed and reducing the wastage of feed in poultry production. The

production of quality day-old broiler chick has major importance in

breederhatchery-broiler production chain. Minimizing the quantity of feed required

to produce a day old-chick results in decreasing the wastage of poultry feed.

In Pakistan, there is no any documented information regarding the

production performances of broiler breeders. Production performances of the broiler

breeders varied from flock to flock according to management practices followed at

the broiler breeder farms. It was necessary to evaluate the performances of broiler

breeders under prevailing field conditions so that we would be able to improve the

32

production efficiency by following good management practices. Efficient

production performances in broiler breeders are responsible for good economic

output of both the broiler breeder farmers and hatcheries and result in better

utilization of poultry feed.


Reproductive performance in female broiler breeders is expressed as

egg production and in males it is expressed as semen production. Hatchability is

an important economic performance indicator for broiler hatching egg industry.

Hatchability means the number of day-old chicks hatched from the total of eggs

incubated and it is affected by several managemental factors at farms, incubation

conditions at hatchery and nutrition values of broiler breeder.

The first priority for diet used in broiler breeders is for maintenance and

development of vital organs. Secondly, diet is used for growth of muscles and bones

and egg production, with deposition of some fat that is necessary for onset of lay.

However if birds get an excess of nutrients they will become obese with an excessive

deposition of fat (Schneider et al., 2008) and heavy with excessive breast muscles.

Excessive production of large follicles in the ovary is observed in overfed birds that

result in erratic oviposition with the production of non-settable eggs such as double

yolk, soft-shelled and shell-less eggs (Renema and Robinson, 2004). Excessive fat

deposit decreases egg production and excessive breast muscles used more dietary

energy for muscle maintenance and as consequence, egg production reduced (De

Beer, 2009).

Field study data revealed that many factors are involved in hatchability of

broiler breeders. Yassin et al. (2008) conducted an epidemiological study on

724,750,444 hatching eggs obtained from 511 breeder flocks and in 24, 234 batches.

33

Random regression model was used to analyze the collected data. They concluded

that hatchability were significantly related with broiler breeder age, strain of birds,

egg storage duration, feed manufacturing company, season, year, as well as hatchery

hygienic and management practices. They further observed a significant interaction

between flock age, egg storage duration at hatchery, strain of birds and season of

year. The observed variation in hatchability among the hatcheries on average was

8%. The average estimated hatchability at 25th week of age was 66%, between 31

and 36 weeks, it increased to 86% and at 65 week of age, it decreased to 50%. On

an average, an extra day of storage beyond 7 days reduced hatchability by 0.2% and

from 7 to 14 day by 0.5%. Eggs obtained from older flocks were more sensitive to

season and less sensitive to prolonged storage. Hatchability was higher during late

summer than spring season. The average estimated difference in hatchability among

strains was 8 percent and among feed company of the breeder farms was 2%. Based

on the very comprehensive study, they concluded that higher hatchability percentage

totally depends upon the good management practices at breeder farms and hatchery

and good hatching egg

quality.

Heier and Jarp (2001) conducted a study to evaluate hatchability on 112 Ross

broiler breeder flocks in different breeding farms. Data were analyzed by using

repeated-measures analysis with the flock-level “interval-specific” hatchability of

the eggs as outcome variable. They concluded that many factors significantly

influence the hatchability. On average, the mean of interval-specific hatchability in

the study was 75.9 percent (95% confidence interval: 75.3 to 76.6%). It was

observed that method of disinfecting of hatching eggs and the weight of birds near

the end of laying period affect the hatchability whereas age and flock size

significantly affected the hatchability except long egg storage time.

34

The previous data revealed that the different managemental and biological

factor affects the hatchability and economic performance but in our climate

conditions, this information is lacking and will be valuable contribution to improve

the flock average hatchability from 75 to 85%.


2.3.1 Epidemiological Evaluation of Economics of Hatchability in Broiler

Breeders

Poultry industry is growing very rapidly, now Grandparents of 5 broiler

strains, Hubbard, Cobb 500, Arbor Acres Plus, Ross 308 and Indian River exist in

Pakistan. Hubbard broiler breeder strain is most popular and has a share of about

50-55%. In this study, Hubbard Classic strain was selected to evaluate the

hatchability and biological performances of broiler breeders. For this purpose, a

complete production data of 20 broiler breeder flocks from 26 to 60 weeks of age

were collected at random for the years 2005 to 2011 (seven years). Data were

collected from the actual records saved at commercial broiler breeder farms. For

data analysis only those flocks were included in study that had the complete records

of growing and laying period. Data were collected on weekly average basis by a

Performa as shown in Table 2.1. The data were evaluated for weekly average egg

production percentage, weekly average hatchable egg percentage, weekly average

egg weight (g) and weekly average egg hatchability. Number of eggs laid per hen

housed, total number of hatchable eggs per hen housed and total number of chicks

produced per hen housed during production period (26-60 weeks) were also

calculated. Feed consumed to produce a hatching egg and one day-old chick per hen

housed was also calculated. Average performances observed from selected flocks

were compared with the strain (Hubbard Classic) standards. Annual effect of day-

35

old chick per hen housed on feed consumption (tons) and feed cost (Rupees) in

Pakistan was calculated. The following parameters of broiler breeder performances

were studied;

2.3.1.1 Egg Production

At the completion of each weak during production period, total eggs laid

during the week were divided by number of remaining females at the end of week.

The resultant figure was divided by 7 (no. of days in a week), again the resultant

figure was multiplied by 100 to get weekly average egg production percentage.

Similarly weekly average egg production was calculated throughout production

period (from 26-60 weeks) for each of 20 selected broiler breeder flocks.

2. 3.1.2 Hatchable Egg Percentage

Eggs laid during each week of egg production period were graded. All

misshapen, cracked, dirty, blood stained, toe punched, elongated etc. eggs were

rejected and only oval shape good quality intact eggs for hatching were selected.

Selected hatchable eggs were divided by total eggs laid; resultant figure was

multiplied by 100 to get weekly average hatching egg percentage. Weekly average

hatching egg percentage for production period (from 26-60 weeks) for each of 20

selected broiler breeder flocks were calculated.

2. 3.1.3 Egg Weight

At the end of each week, 30 eggs from each house of the selected flock were

weighed to get average egg weight. Egg weight was measured in grams. Average

egg weights were recorded during the production period (from 26-60 weeks) of

each selected flock.

36

2 .3.1.4 Egg Hatchability

For each selected flock, all the chicks hatched out of weekly incubated eggs

were divided by total weekly incubated eggs and resultant figure was multiplied by

100 to get weekly average egg hatchability percentage. Similarly weekly average

egg hatchability percentage of each selected flock (from 26-60 weeks) was

calculated.

2 3.1.5 Hen Housed Eggs

At the completion of each week of production period (from 26-60 weeks)

for each flock, total eggs laid were divided by the number of hen housed females

(number of females at the start of 25 week) for that flock to get hen housed eggs.

2. 3.1.6 Hen housed Hatchable Eggs

For each selected flock, at the end of each week of production period (from

26-60 weeks) total selected hatching eggs were divided by the number of hen housed

females to get the number of hen housed hatching eggs.

2. 3.1.7 Number of Chicks Produced per Hen Housed

Total chicks produced at the end of each week of selected flock were divided

by the number of hen housed females for that flock to obtain the number of chicks

produced per hen housed for that flock.

37

2 3.1.8 Feed Consumption per Hatching Egg

Total feed consumed in grams by males and females till the end of any week

of production period of a selected flock was divided by the number of total hatching

eggs produced at the end of that week to get feed consumed for the production of a

single hatching egg for that particular selected flock.

2. 3.1.9 Feed Consumption per One Day-old Chick

Total feed consumed in grams by males and females till the end of any week

of production period of a selected flock was divided by the number of total hatched

good quality day-old chicks at the end of that week to get feed consumed for the

production of a single day-old chick for that particular selected flock.

2. 3.1.10 Male and Female Body Weight

The average of weekly body weights of males and females in grams during

production period (26 to 60 weeks) were recorded for each of 20 selected flocks.

2 3.1.11 Spiking

Replacement of old males with young males (spiking) during the last phase

was also considered while collecting of selected breeder flock.

2.3.2 Data Analysis

The PROC ANCOVA procedure of the SAS package (SAS Institute, 2002)

was performed to test the equality of slopes across flock, where flock was the main

effect and laying period (L) was the covariable, assuming the following model:

Yij = µ+Fi + Lj + eij

38

where Yij is the dependent variable (Egg production, hatchable egg percentage, hen

housed eggs and hen housed hatching eggs, male and female body weight, egg

weight, egg hatchability, number of chicks produced per hen housed and feed

consumption per day-old chick and spiking); µ is the population mean; Fi is the

effect of the ith flock; Lj is the linear effect of the jth laying period and eij is a

random error term. Regression lines corresponding to the analyses described above

were fitted to the data and the regression equation was presented.

The relationship between hatchability, day-old chicks and feed consumption

were evaluated by calculating correlation coefficients for total hatchability, day-old

chicks and feed consumption. The data collected were analyzed with Pearson’s

coefficients of correlation (r) and it was achieved using SAS software. The average

production performances were compared with strain standards by simple t-test by

using the procedure of SPSS 16.0 software at the 0.05 level of significance.

2.4 RESULTS AND DISCUSSION

2.4.1 Egg Production, Hatchable Egg Percentage, Hen Housed Eggs and Hen

Housed Hatching Eggs

Plot of weekly egg production and fitted curve is presented in Figure 2.1.

Regression analysis showed that egg production was described by a simple linear

equation. The curve showed that average weekly egg production percentage

increased rapidly till 35 week and then decreased slowly during the rest of

production period (26-60 weeks). The weekly peak egg production was observed as

80.2% during the 35 week of age. Average egg production percentage of different

egg production periods were observed as 44.1 (26-30 weeks), 78.1 (31-35 weeks),

78 (36-40 weeks), 72.7 (41-45 weeks), 67.6 (46-50 weeks), 63 (51-56 weeks) and

56.4% (56-60 weeks). The average egg production in broiler breeder flocks was

found as 65.7% (ranging 58.3 to 74.3%). Maximum and minimum weekly peak egg

39

productions in the individual flocks were recorded as 90 and 74.3%, respectively. In

this epidemiological study, average egg production percentage remained below

standard of Hubbard Classic broiler breeder strain throughout production period but

this difference was very wide at early and peak production period (Figure 2.1). This

production difference was found minimized during 35-41 weeks and after that going

to increase till the end of production period. Egg production percentage of individual

flocks varied differently from that of standard, only few flocks showed above

production than standard but most of the flocks showed below production as

compared to standard.

Plot of weekly hatchable egg percentage and fitted curve is given in Figure

2.2. This showed that average weekly hatchable egg percentage increased gradually

till 39 week and then decreased very slowly after 50 week during the rest of

production period (26-60 weeks). The average weekly hatchable egg percentage was

found as 96.33% (ranging from 78.3 to 98.8%). The average hatchable egg

percentage in the individual broiler breeder flocks was 96.33% (ranging from 93.8

to 97.7%).

A trend of total eggs laid per hen housed in broiler breeder depending on

weeks (26-60) is shown in Figure 2.3. Maximum hen housed eggs laid by broiler

breeder flocks was observed as 5.46 during 34 week and minimum hen housed eggs

was found as 2.1 during 26 week of age. Average number of hen housed eggs laid

by broiler breeder flocks at the age of 60 week was recorded as 149.8 eggs (ranging

from 119.6 to 174.0 eggs).

There was an increasing trend of hatching eggs produced per hen housed in

broiler breeders during 26 to 60 weeks of age (Figure 2.4). Maximum weekly

hatching eggs laid per hen housed in broiler breeder flocks was found as 5.2 during

32-36 weeks and minimum was as 1.9 during 26 weeks of age. Average number of

40

hatching eggs laid per hen housed in broiler breeder flocks at the age of 60 week

was recorded as 145.1 (ranging 114.9-167.9 hatching eggs).

Hen housed eggs (total egg/hen housed) and hatching eggs per hen housed

remained below breed standard throughout production period but this difference

increased directly with increase in production period. When flocks were observed

individually, only two flocks laid total and hatching eggs per hen housed above

standard while all other flocks laid hen housed eggs below strain standard. Hatching

egg percentage out of total eggs laid remained very close to breed standard

throughout production period.

15

Table 2.1: Performa for broiler breeder performance record

Flock No. ----------------- No. of Females -------

Flock History ------------ No. of Males ---------- Flock

Hatch Date --------- No. of Hen house Female-----

Wk

(no)

Prod

(%)

HE

(%)

Egg

wt.

(g)

Hatch

(%)

TE/

HH

HE/

HH

Chicks/

HH

Feed/d

(FM)

(g)

Feed/d

(M)

(g)

Feed/

(HE)

(g)

Feed/

Chick

(g)

Female

Body

wt. (g)

Male

Body

wt.

(g)

TE/

Week

HE/

Week

Female

(no.)

Male

(no.)

Spiking

(no.)

25

26

27

28

-

-

-

-

60

TE = Total eggs FM = Female HH = Hen housed females M

= Male HE = Hatchable egg WK= Week

43

. There is limited literature available on above parameters which studied in this

survey. A variation in egg production percentage with age in this study is similar to

previous studies of some scientists who observed that reproduction efficiency of

broiler breeders decreased with flock age because of change in internal egg

composition or ratio, larger egg weight and poor egg shell quality

(Leeson and Summers, 2000; Elibol and Brake, 2006; Tona et al., 2004; Joseph and

Moran, 2005; Al-Basham and Al-Harbi, 2010). Similarly, Brommer and Rattiste

(2008) studied that the effect of age is more significant on females than on males in

wild birds.

2.4.2 Male and Female Body Weight

Plots of average male and female body weights and fitted curve are depicted

in Figure 2.5. Regression analysis showed that body weight was described by a

simple linear equation. Average body weight of male and female had trended to

increase throughout production period (26-60 week) in broiler breeder. Average body

weight for male and female at 60 week of age was found as 4785 and 3929 g,

respectively (Figure 2.5). Maximum and minimum body weight for individual flock

at the 60 week of age was observed as 5248 and 4620 g for male and 4307 and 3619

g for female, respectively. This variation in average body weight in individual flocks

was due to management practiced followed at broiler breeder farms. As for as

individual flocks were concerned, those flocks (e.g. flock numbers

10, 15 and 19) that had trend to increase body weight (male and female) gradually

(Table 2.2) showed better hatchability and yielded maximum number of chicks per

hen housed (Figure 2.9). The flocks (e.g. flock numbers 02, 05 and 16) which were

showing abrupt changes in body weights

44

Figure 2.1: Trend-cycle of egg production in broiler breeder


45

Figure 2.2: Trend-cycle of hatching egg (%) in broiler breeder


46

Figure 2.3: Trend-cycle of hen housed eggs in broiler breeder


47

Figure 2.4: Trend-cycle of hen housed hatching eggs in broiler

Breeder depending on weeks of age

particularly male body weights (Table 2.2) resulted lower hatchability and yielded

minimum number of hen housed chicks (Figure 2.9).

The results of the current study are in line with the findings of Djermanovic

et al. (2013), who reported that at the beginning of the productive cycle (24 week of

48

age) for male of Ross 308 hybrids, average body weight was found as 3030 g, and

for Cobb 500 male average body weight was 3045 g. However, in the current study

the male average body weight for Hubbard was 3531g. In the 42nd and 61st weeks of

age, average body weight of Ross 308 was observed 4306 and 4908 g, respectively.

Similarly, at the same age, Cobb 500 had 4323 and 4918.5 g while Hubbard had 4533

and 4820 g respectively. These workers also determined correlation coefficient and

reported that male body weight had positive influence on laying intensity of fertilized

eggs till 58th week of age (Ross 308) and 60th week of age (Cobb 500), while on

hatchability of chicks it had positive influence till 58th week of age for both hybrids.

Other workers Djermanovic (2010), Djermanovic et al. (2009) and Mirovic et al.

(2010) also confirmed similar results during the productive cycle with a little higher

body weights of the males than that of standard weights. Moreover, Celeghini et al.

(2001) reported that Ross hybrid broiler parents had 3152, 4990 and 5333 g of body

weight between age of 24 to 27, 40 to 43 and 60 to 63 weeks, respectively. Moreover,

Pandurevic et al. (2013) reported that at the beginning of the production cycle (24

weeks of age) for hen of Ross 308 hybrids, average body weight was found as

2680.40 g, while for Cobb 500 hen average body weight was 2697.80 g. In the 42nd

and 61st weeks of age, average body weight of hen (Ross 308) observed as 3565.10

and 3841.50 g, respectively. Similarly, at the same age, Cobb 500 hen had average

body weight 3599.05 and

49

Figure 2.5: Trend of male and female body weights in broiler

breeder depending on weeks of age

Table 2.2: Flocks with maximum and minimum number of day-old chicks per hen

housed

50

Flocks with gradual increase in body

weights (during production periods)

Flocks with abrupt change in body

weights (during production periods)

Individual flock

Numbers Chicks/hen housed

Individual flock

Numbers Chicks/hen housed

19 142.1 16 86.6

10 137.1 2 96.2

15 130 5 100.8

3850 g respectively. In the current epidemiology study, the female average weights

at the same age (42 and 61wk) were 3750 and 3929 g respectively.

51

2.4.3 Egg Weight

As broiler breeder aged, the egg weight increased throughout the production

period (26-60 week) and the average egg weight during production period was found

as 64.7 g. Average egg weight of different egg production periods were observed as

55 (26-30 week), 61.6 g (31-35 week), 64.4 g (36-40 week), 66.2 g

(41-45 week), 67.5g (46-50 week), 68.5 g (51-56 week) and 69.5 g (56-60 week).

Egg weight was increased (1.32g per week) during early stages and then gradually

decreased to (0.14g per week) during later stages of egg production periods (Figure

2.6). The average egg weight in broiler breeder flocks at 60 week was found as 69.8

g (ranging from 67.2 to 73.4g). Average egg weight observed in this study remained

very close to standard till 50 week and above during rest of production period.

Average egg weight observed during production period was slightly above (+0.62 g)

than standard weight but egg weight increased rapidly after 50 week that results in

higher average egg weight (+2.05 g) at 60 week than strain standard.

In this study, it was observed that the individual flock number 19 having

minimum average egg weight during production period showed best hatchability and

yielded maximum number of day-old chicks per hen housed. Similarly, it was also

observed that the individual flock number 16 having maximum average egg weight

during production period showed poorest hatchability and yielded minimum number

of day-old chicks per hen housed (Table 2.3).

Gualhanone et al. (2012) reported that egg weight of Cobb broiler breeder

was increased at 30 week (59.48g) to 60 week (70.39g) of age. Many other studies

52

Figure 2.6: Trend-cycle of egg weight in broiler breeder depending on

weeks of age

also showed that egg weight increased with the breeder age and older breeders with

heavier eggs produced heavier chicks (North and Bell, 1990; Suarez et al., 1997;

Novo et al., 1997; Adamski, 2008). Tona et al. (2004) observed that the weight of

eggs laid by Cobb hens aged 35 and 45 weeks was 66.44 and 70.56 g, respectively,

53

and it was higher than in our experiment, the difference may be due to strain

difference. This increase in egg weight with age was due to the increasing weight of

the yolk rather than white, whose proportion in the egg mass decreased with age.

2.4.4 Egg Hatchability and Number of Chicks Produced per Hen Housed

Average weekly egg hatchability increased till the 39 week and then

decreased during the rest of production period in broiler breeders. The weekly peak

egg hatchability (86.4%) was observed during the 38 and 39 weeks of age (Figure

2.7). Average egg hatchability of different egg production periods were observed as

67.8, 84.2, 86.1, 85.0, 82.1, 77.8 and 71.7% for periods of 26-30, 31-35, 36-40,

41-45, 46-50, 51-56 and 56-60 week, respectively. The broiler breeder flock’s

average egg hatchability observed was 79.3% (ranging from 69.7 to 84.6%).

Maximum and minimum weekly egg hatchability in individual broiler breeder

flocks was observed as 90.1 and 10.1%, respectively.

Number of chicks produced per hen housed in broiler breeders during

production period was increased with advancing of age (Figure 2.8). Maximum

weekly hatching chicks per hen housed in broiler breeders was found as 4.5 during

32-36 weeks and minimum was observed as 1.5 chicks during 26 week of age.

Average number of chicks hatched out per hen at the age of 60 week in the broiler

breeders was found as 119.10 (ranging from 86.6 to 142).

Table 2.3: Hatchability of flocks with maximum and minimum average egg weight

Parameters

Individual Flock No. 16

(Max. Egg wt.)

Individual Flock No. 19

(Min. Egg wt.)

54

Average egg weight (during

production period)

66.1±5.68 g 63.7±5.02 g

Egg weight (at 60 week) 73.4 g 69.4 g

Female weight (at 60 week) 4300 3650

Average hatchability

(during production period)

69.7±0.09% 84.6±0.05%

Number of chicks per Hen

housed (at 60 week)

86.6 142.1

Average egg hatchability remained below standard hatchability but this

difference was very high during early and late stages of production period. Number

of chicks produced per hen housed remained below standard but this difference

increased directly with the increase in production periods.

55

As for as individual flocks were concerned, there was a strong positive

correlation (r2 =0.980) between the hatchability and the number of chicks produced

per hen housed as shown in Fig. 2.9 and this relation was highly significant (P-

value= 0.000).

In this study hatchability in broiler breeder ranged from 69.7 to 84.6% with

average hatchability 79.3%. Similarly, a study conducted in Norway in 1999 showed,

an average hatchability and fertility in Ross 208 broiler breeders were 86.6 and

72.7%, respectively (Nordvoll, 1999). The observed hatchability varied in different

countries as in United Republic of Tanzania 50-100% (Minga et al., 1989), in

Burkina Faso 60-90% (Bourzat and Saunders, 1990), in Senegal 60-95% (Gueye,

2003), in Uganda 70.8-85.7% (Illango et al., 1999) and 45-75% (Byarugaba et al.,

2002) and in Nigeria 70.1-78.3% (Sola-Oja 2011). Different workers also reported

that 80.9-81.7, 69.7, 78, 82 and 84.9% hatchability in Ethiopia, Philippines, Sudan,

Zambabwe and Uganda, respectively (Tadelle and Ogle, 1996; Eugene, 2004;

Khalafalla, 2000; Kusina et al., 2000 and Kirunda et al., 2010).

In this study, average egg hatchability dropped rapidly after 50 week due to

increase in egg weight as hatchability is different for different egg sizes as evidenced

by different scientists (Williamson and Payne, 1978; Mandlekar, 1981). Mandlekar

(1981) reported that hatchability for medium-sized (51-56 g) and smallsized eggs

(45-50 g) from broiler breeders were 88.2 and 84.8%, respectively.

56

Figure 2.7: Trend-cycle of egg hatchability in broiler breeders


57

Figure 2.8: Trend-cycle of number of chicks per hen housed in broiler breeder


58

Figure 2.9: Correlation between hatchability and number of chicks per hen

housed in broiler breeder.

r = Correlation between number of chicks per hen housed and hatchability

Asuquo and Okon (1993) reported that hatchability of smaller eggs was lower

compared to larger and medium sized eggs. Abiola et al. (2008) reported the best

hatchability for medium sized eggs in Anak broiler eggs. Gonzalez et al. (1999) also

suggested that for maximum hatchability average weight eggs should be incubated.

59

North and Bell (1990) observed best hatchability when egg weight ranged between

55-65 g in broiler breeder.

2.4.5 Feed Consumption per Hatching Egg and to Produce One Day-old

Chick

During production period (26-60), average feed consumed to produce a hatching egg

per hen housed in broiler breeder reduced rapidly till 33 week and then slowly during

rest of production period (Figure 2.10). At the 60 week of age, average feed

consumed to produce one hatching egg was 395 g (ranging 295 to 708g) in broiler

breeder flocks. Similarly, average feed consumed to produce one day-old chick per

hen housed in broiler breeder reduced rapidly till 34 week and then slowly during

rest production period (Figure 2.11). At the 60 week of age, average feed consumed

to produce one day-old chick was 486 g with ranging from 351 to 939 g in broiler

breeder flocks. This wide range of variation for average feed consumption to produce

one hen housed hatching egg and day-old chick in individual flocks was due to

management practiced followed at broiler breeder farms.

From this field study, it was observed that there was a strong negative

correlation (r2 = -0.833) between the number of chicks produced per hen housed and

feed consumed to produce one day-old chick per hen housed as shown in

Figure 2.12 and this relation was highly significant (P-value = 0.000).

60

Figure 2.10: Trend-cycle of feed consumption (g) per hatching egg in broiler

Breeder depending on weeks of age

y = - 225.72x + 5980.9

-5000

0

5000

10000

15000

20000

25000

26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60

weeks

Feed/HE

61

Figure 2.11: Trend-cycle of feed consumption (g) per day-old chick in broiler

breeder depending on weeks of age

y = - 365.41x + 9504.2

-5000

0

5000

10000

15000

20000

25000

30000

35000

26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60

weeks

Feed/chick

62

Figure 2.12: Correlation between numbers of chicks per hen housed and feed

consumption per day-old chicks in broiler breeder.

r = Correlation b/w number of chicks per hen housed and hatchability

2.4.6 Spiking

In broiler breeder flocks, only 30% flocks were spiked. Spiking of young male

with aged male was started from 41 week and continued to 55 week but spiking

percentage varied in different weeks of broiler breeder flock age as shown in Figure

63

2.13. In spiked flocks, only 26.87% male and in selected flocks 9.59% males were

spiked during production period.

Literature showed that male fertility decreased in obese males (Hocking and

Duff 1989); desire to mate is reduced in aged male (McGary et al., 2003) and

excessive body weight gain in males result in unsuccessful mating (McGary et al.,

2003). Similarly, Ottinger (2001) showed that testicles become shrinked and their

ability to produce semen reduced in older Japanese quail. As the fertility of broiler

breeder males decreases with age, juvenile males are spiked in older flock (above 45

week). These young (spiked) males actively mate with hen and at the same time

stimulate older males to resume mating thereby improving overall flock fertility.

It may be concluded from this study the spiking practices in broiler breeders

in Pakistan is not popular because few flocks were spiked. This may be due to avoid

the risk of any disease incidence in broiler breeder flocks because many infectious

diseases are popular in Pakistan.

2.4.7 Comparison of Production Performance with Strain Standard A summary

of production performances of (Hubbard Classic strain) broiler breeders is shown in

Table 2.4. Production performances (egg production, egg weight, and egg

hatchability, total eggs/HH, hatching egg/HH, total chicks/HH, feed/hatching egg,

feed / day-old chicks and female body weight) differed significantly (p≤0.05) while

hatching eggs percentage and male body weight

64

Figure 2.13: Trend of male spiking percentage in broiler breeder depending

on weeks of age

differed non-significantly (p≥0.05) from strain standard due to different management

practices followed during production and rearing periods.

y = 0.0191x - 0.0399

-0.5

0

0.5

1

1.5

2

2.5

26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60

weeks

spiking%

spiking%

65

2.4.8 Annual Effect of Hatchability (Day-old chick /Hen House) on Feed

consumption and Feed Cost

Annually about 12 million parent broiler breeder day-old chick are housed in

Pakistan for the production of good quality day-old broiler chicks (PPA, 2011). As

observed in this study 486 (g) feed is consumed to produce a single day-old chick.

These 12 million broiler breeders consumed 5832 ton of feed to produce 12 million

day-old broiler chicks (one day-old chick/ hen housed). Due to poor management

practices followed in Pakistan, less numbers of day-old chicks per hen housed are

produced (119.1 against the Hubbard standard 139.0). Annually, 116056.8 tons of

feed consumed by 12 million broiler breeder are wasted because of averagely 19.9

fewer number of day-old chicks produced per hen housed. So, poor management

practices in broiler breeders are responsible for the 4.12 million $ annual loss for

poultry industry as shown in Table 2.5.

It was concluded that observed average production performances of broiler

breeders in Pakistan are below the strain standards. The number of day-old chicks

per hen housed and hatchability percentage in broiler breeders have great impact on

the economics of poultry production. It is imperative, to improve the management

practices at broiler breeder’s farms and broiler hatchery to improve hatchability and

number of day-old chicks per hen housed so that the feed consumption per day-old

chick may be reduced.

Table 2.4: Comparisons of the average performance of broiler breeders with that of

strain standards

Parameters

Average

performance

± SD(26-60wks)

*Breed

Standards

Differences

(±)

P-Value

66

Egg Production% 65.7±4.10 73.21 - 07.51 0.000(2-tailed)

Hatching eggs % 96.7±1.09 96.71 - 0.01 0.118(2-tailed)

Egg weight (g) 64.7±1.01 64.08 + 0.62 0.017(2-tailed)

Egg weight at 60 week (g) 69.85±1.43 67.8 + 2.05 0.000(2-tailed)

Egg Hatchability% 79.3±4.28 84.62 - 05.3 0.000(2-tailed)

Total eggs/Hen housed 149.8±12.84 171.1 - 21.3 0.000(2-tailed)

Hatching eggs/Hen housed 145.1±12.42 164.1 - 19 0.000(2-tailed)

Total chicks/ Hen housed 119.1±13.24 139 - 19.9 0.000(2-tailed)

Feed (g)/Hatching egg 395.45±83.56 335 +60.45 0.004(2-tailed)

Feed (g)/Day-old chicks 486±122.06 396 +100 0.004(2-tailed)

Female body weight (g) 3929±183.53 3815 +114 0.009(2-tailed)

Male body weight (g) 4785±250.64 4720720

47.20

+65 0.263(2-tailed)

*Breed standards were taken from Hubbard Guide Book.

Table 2.5: Effect of day-old chick /hen housed (hatchability) on feed consumption

and feed cost

Description of parameters Numerical Value of

parameters

Observed Average Feed consumption/day-old chick= X 486 (g)

*Annual broiler breeder (FM)** reared in Pakistan = Y 12 million

Annual effect of one day-old chick/HH on Feed=Z=(X×Y) 486×12000000=5832000000

(g) = 5832000Kg = 5832 ton

Day-old chicks (Breed Standard at 60 week)/HH=M 139 chicks

67

Observed (day-old chick/HH) at 60 week in Pakistan=N 119.1chicks

Difference of day-old chick from Breed Standard at 60

week =O= (M-N) - 19.9 chicks

Annual Feed wastage due to low Hatchability (day-old

chick/HH) in Pakistan=P=(O×Z)

19.9 × 5832 = 116056.8 ton

Feed

Annual Economic loss of low hatchability in

Pakistan=K=(P× one ton feed rate in Rupees)***

116056.8 × 38000 = 441.01

million (Rs) =4.12million$

*Total number of broiler breeders in Pakistan was obtained from annual report of PPA

(Pakistan poultry association) for 2012.

** FM= Female number

***Feed cost/ton was calculated from the price list of Sadiq Feeds (Biggest poultry group

in Pak.) per 50 Kg Feed bag (Rs.1900) for 2012.

Chapter 3

EFFECTS OF EGG SIZE (WEIGHT) AND AGE ON EGG

QUALITY CHARACTERISTICS OF BROILER BREEDER

68

3.1 INTRODUCTION

The fertile egg provides the physical protection and all nutritional

requirements for the developing embryo during the incubation period. Egg quality

characteristics greatly influence the process of incubation by relating with the chain

of both physiological and energetic features of the developing embryo. Any infringe

in this chain of interactions may result in the mortality of growing embryo. In

reproductive poultry flock, it is imperative to attain a large number of eggs with

normal structure, optimal exterior and interior qualities. Egg quality generally refers

to several standards which define both internal and external quality of egg. There is

need to understand the factors particularly egg size and age of breeder that affect egg

external and internal qualities and percentages of egg components. The hen’s egg

normally consists of the yolk (30-33%), albumen (5660%) and the shell 9-12%

(Stadelman, 1995).

Sahin et al. (2009) reported that as the hens’ age increased, the weight of their

eggs were generally higher and the shape changed (the eggs become more elongated).

However, the white characteristics (index, Haugh units) and eggshell traits (weight,

thickness or strength) deteriorated with advancing the reproductive age (Van den

Brand et al., 2004; Akyurek and Okur, 2009). A significant role of egg white quality

in the embryo-genetic process for maintaining the normal white

41

viscosity and elasticity that might be necessary for sufficient use of ovomucin by the

developing embryo during incubation (Reijrink et al., 2008). However, studies

showed that as the laying season advances, some white characteristics deteriorate

(Nowaczewski et al., 2010). Coutts and Wilson (1990) examined consecutive

reduction in the number of Haugh units in hen eggs, on average by 1.5-2 points per

69

laying month. Similar results were obtained in Japanese quails (Nowaczewski et al.,

2010). In addition, the yolk index is also related to the strength of the vitelline

membrane, which is an equally important component of the hatching egg (Reijrink

et al., 2008). The positive correlation between the number of day-old chicks and shell

thickness or strength (Dohnal et al., 1986) can be elucidated by the fact that eggs

with thicker shell are less steam-permeable. This was confirmed by Christensen

(1983) and Bennett (1992), who found better hatchability in hens and turkeys from

eggs with a thicker shell. Conversely, Yilmaz and Bozkurt (2009) found significant

deterioration in the shell characteristics as the age of laying hens increased. These

researchers examined lower shell thickness, strength and density in hens aged 80

weeks as compared with hens at the peak of lay (aged 28 weeks). Moreover, the

influence of shell quality on hatchability results in Japanese quails was verified by

Khurshid et al. (2004).

A good correlation between breeder age and egg size was previously

demonstrated by Raju et al. (1997). The quality of hatching eggs affects the

hatchability as well as the quality of hatched day-old chicks (Moyle et al., 2008;

Yoho et al., 2008). Some researchers also indicated that there is a relationship

between hatchability results and egg specific gravity. For example, Dohnal et al.

(1986) observed the presence of a significant positive correlation between this

characteristic and hatchability. As follows from the findings of Szczerbińska (1996),

the value of egg specific gravity decreased significantly with hen’s age. The yolk to

white ratio varies widely with the egg size (Marion et al., 1964). Age of hen also

affects the yolk, albumen and eggshell weight percentages of the egg (Fletcher et al.,

1981; Akbar et al., 1983; Danilov, 2000). As hen ages, yolk weight increases (Leeson

and Summers, 1989), although the effect on dry albumen weight seems very little

(Hurnik et al. 1997). The yolk weight percentage is less in smallsized eggs compared

to large-sized eggs (Kaminska and Skraba, 1991). Therefore, the eggs (larger eggs)

70

obtained from older and forced molted hens are significantly different than those

from younger birds (which lay smaller eggs). The shape of an egg can vary depending

on the size, age and health of chicken (King,ori, 2012). Normally, the shape of the

egg is determined by the pressure exerted by the walls of oviduct within the hen. A

good healthy hen has strong muscles which push the eggs through fairly quickly and

mold the egg’s shape as the shell is being formed.

Broiler breeders have a genetic tendency to higher feed intake than laying

hens, which often results in their undue fatness. As a result, the reproductive indexes,

especially the hatchability results, decrease. Therefore, it is imperative to in detail

investigate all components of this problem in those birds, together with a detailed

analysis of egg quality, including the whole reproductive period. The literature

provides the results of some studies relating to the influence of broiler breeder age

on egg quality and not on egg size. However, generally the beginning and the end,

and possibly the middle of the reproductive period were compared

(Lapao et al., 1999; Tona et al., 2004; Cherian, 2008). Therefore, the aim of the

experiment was to study the effect of egg size and age on egg quality during early,

mid and late stage of production period in Hubbard Classic broiler breeder strain.


3.2.1 Effect of Egg Weight (Size) and Age of Broiler Breeder on

Egg Quality Characteristics

The egg has the function to supply the embryo chick with protection and

nutrients for its development during incubation. Egg weight has been associated with

chick weight and posterior broiler performance (Willemsen et al., 2008). Konteka (et

al., 2012) showed that egg weight increased with age but at a certain age egg weight

can also be increased with the increased intake of dietary fat particularly linoleic acid

(Grobas et al., 1999), protein (Lopez and Leeson,

71

1994) and certain amino acids such as methionine and lysine (Bowmaker and Gous,

1991).

Abudabus (2010) studied that hen age influenced egg weight (p≤0.001), the

older the hen the heavier the egg. He observed that egg weight ranged from 58.2 g

for Cobb strain at 26 week to 72.8 g for the same strain at 44 weeks of age. While for

the Ross strain no significant difference was detected for the two age groups, 67.4

and 66.4 g for 32 and 36 weeks of age, respectively. Similarly in Hubbard Flex hens

Adamski (2008) found that the mean weight of eggs increased by about 2.5 g within

each three-week interval between consecutive egg quality tests.

Narushin and Romanov (2002) concluded that physical quality of the egg play

an important role in the development of embryo and successful hatching.

Egg weight, shape index, shell thickness, shell porosity and the proportions of the

egg contents were the most influential on hatching results. The average values of

these parameters meet the requirements of embryo's development and result in good

hatchability. They further concluded the eggs not having these parameters in the

average range can hatch better if they had shell thicker than average values and higher

albumen viscosity. Similarly Konteka et al. (2012) analyzed the physical

characteristics, morphological composition and quality of individual components of

the eggs of Cobb 500 broiler breeders during the first year of reproduction. The

research material was hatching eggs (280 pcs), whose quality was assessed 7 times

in the reproductive season at 5-week intervals. The eggs were examined when the

hens were aged 26, 31, 36, 41, 46, 51 and 56 weeks (40 eggs for each age). The

following characteristics were evaluated: egg weight (g); egg shape index (%); egg

specific gravity (g/cm3); shell thickness (mm); average number of pores in the

eggshell (pcs/0.25 cm2); yolk, white and shell weight (g) and their percentage in the

egg mass; yolk index (%) and the number of Haugh units. The investigations proved

72

that as the reproductive season of hens progressed, the weight of their eggs increased

due to the increase in the yolk weight, because its percentage in the egg with age. Egg

shape and egg specific gravity were significantly decreased with age. The directional

factors of the regression equation (b) for egg shape and egg specific gravity were -

0.5 and -0.002, respectively. In consecutive weeks of hens’ age the weights of yolk

and white increased significantly by 1.3 and 1.1 g, respectively. No statistically

significant reduction in eggshell thickness was observed as hen age increased.

Pirsaraei et al. (2011) also studied the egg quality characteristics in broiler breeder

flocks and found that eggs from older broiler breeders (aged 58 weeks) characterized

higher yolk weight and lower white weight, by 1.25 g on average as compared with

birds in the initial period of egg laying (22 weeks of age). Adamski (2008) obtained

slightly different results in broiler breeders. For yolk weight and white weight

characteristics, he observed a positive trendcycle, where the directional factor of

linear regression was 0.65 and 1.27, respectively. The results of studies on broiler

breeders made by Amem and AlDaraji (2011) provided different results. They found

a higher yolk height value

(best yolk quality) in birds aged 58 weeks, as compared with the age of 54 and 62

weeks. Similar results were observed by Ulmer-Franco et al. (2010) who studied the

effect of age on proportion of yolk and albumen and concluded that eggs of the young

flocks had a less proportion of the yolk and a larger proportion of the albumen when

compared to the eggs from old flocks.

Amem and Al-Daraji (2011) studied the specific gravity in the eggs of broiler

breeders. When the hens were aged 54, 58 and 62 weeks, the values of specific

gravities were 1.081, 1.077, and 1.060 respectively. Pirsaraei et al. (2011) compared

egg specific gravity in Ross 308 hens aged 22, 34, 48 and 58 weeks. They observed

that effect of age on specific gravities were nonsignificant. Some researchers also

73

indicated that there is a relationship between hatchability results and egg specific

gravity. For example, Dohnal et al. (1986) observed the existence of a significantly

positive correlation between the egg specific gravity and hatchability of broiler

breeder flocks. As followed from the findings of Szczerbińska et al. (1996), the value

of egg specific gravity reduced significantly with hen age.

Lapao et al. (1999) conducted two experiments to study the influence of age

and storage duration on egg albumen quality in the broiler breeder. The eggs were

collected from four commercial flocks of the Peterson Minibro Shaver strain aged 32

and 54 weeks kept under the same management and nutritional values. These eggs

were stored for the periods of 0 (fresh), 1, 4, or 8 days and then incubated at 16°C

and 78% relative humidity. In experiment 1, prior to each setting albumen pH and

albumen height were recorded and at 0, 12, 24, 38, 60 hour of incubation in

experiment 2 when flocks were 42 and 59 weeks of age. They observed 0.95 higher

pH of albumen in eggs stored for 8 day than in fresh eggs but most of this increase

was during the first 4 day of storage. There was increased (p≤0.05) of pH with flock

age at 0 day of storage, but at 8 day of storage, these differences were negligible.

Albumen height and embryo viability were decreased (p≤0.05) with the increase in

hen age and storage time. Interaction of both factors (age and storage time) was

substantial with regression coefficients of viability on days of storage being -0.82

and -1.92% at 32 and 59 week of age. The results suggested the decline in hatchability

with presetting storage started at day-one of lay most probably due to egg albumen

quality deterioration.

Wolc et al. (2010) conducted a study on broiler breeders to observe the

relationship between heritability and internal and external egg quality characteristics

at 48 week of age. They observed that egg quality traits, egg weight, haugh units,

specific gravity and weight loss had heritability 0.60, 0.38, 0.38 and

74

0.53 respectively.

3.3 MATERIALS AND MRTHODS

3.3.1 Selection of Birds and Experimental Site

In this experiment, a commercial broiler breeder flock, Hubbard Classic strain

(at 25 weeks of age) was selected for study, located in Islamabad territory. A total of

2000 Hubbard Classic females and 180 males (male to female ratio, 1: 11), close to

standard body weights were selected and reared separately in the poultry house. Male

to female ratio was kept constant throughout production period. Any male observed

sick or weak during the production period was immediately replaced with good

quality healthy male from spare male kept at farm. Birds were vaccinated according

to local vaccination program and fed according to recommendation of Hubbard

Classic strain. The composition of feed provided to birds during 25-26 weeks of age

is given in Table 3.1. All other management practices during production periods (25-

60 weeks) were followed according to recommendations of Hubbard Classic strain.

3.3.2 Collection and Selection of Eggs

All the eggs laid during 4-8 hour of light periods, from selected and separated

broiler breeders, were collected from nests at interval of one hour, at early (30 week),

middle (45 week) and late stage (60 week) of production period. All substandard eggs

like misshapen, cracked, dirty, blood stained, toe punched and elongated etc. were

rejected and only oval shape good quality intact eggs were selected for hatching. The

930 eggs were selected from the hatching eggs at early, mid and late stage of

production period and equally distributed into three egg-sized categories (small,

medium and large). Ten eggs from each egg category (having

310 hatching eggs) were analyzed for the following egg quality parameters at early,

mid and late stage of production period. The plan of study is given below in Table

3.2.

75

3.3.3 Measured Egg Quality Parameters

The study of egg quality parameters was conducted within 24 hours of egg

laying, at the Feed Testing Laboratory, in Poultry Research Institute Rawalpindi.

The parameters studied were;

3.3.3.1 Egg Weight

All the eggs of each egg weight category were weighed individually by an

electronic balance to calculate their average egg weight in grams.

3.3.3.2 Shell Weight

The shells of the broken eggs were washed, air-dried and then weighed to

measure shell weight in grams to calculate the shell weight percentages of egg.

3.3.3.3 Shell Thickness

Shell thickness of all 10 eggs of each egg weight category was measured

without the shell membrane with a digital caliper with a sensitivity of 0.001 mm at

broader, equator and pointed end of the fertile egg. The average shell thickness was

measured by the following formula

Shell thickness = (Shell thickness at broader end + Shell thickness at

Equator + Shell thickness at sharp end) / 3

3.3.3.4 Yolk Weight

All the 10 eggs of each egg weight category were broken open; yolks were

separated and weighed individually to calculate yolk weight percentage by the

Table 3.1: Composition of broiler breeder layer diet (30, 45 and 60 week)

Ingredients

Quantity

(g/kg) Ingredients

Quantity

(g/kg)

Maize 616.50 DL-Methionine 1.56

76

Rice polish 80.00 Threonine 0.07

SBM Hydro (48%CP) 122.92 L-Tryptophan 0.01

Sun flower meal 39.89 Phytase 30 pure(10000) 0.03

Guar meal 20.00 Mineral premix1 0.47

Fish meal (50%CP) 40.00 Vitamin premix2 1.00

Marble chips 74.19 Eneramycin (4%) (AGP) 0.13

Salt 1.44 Antioxidant 0.07

Sodium Bi Carbonate 1.606 Total 1000

Calculated Analysis

ME (K Cal/kg) 2800 Sodium (%) 0.16

Crude Protein (%) 15.5 Chloride (%) 0.19

Crude Fat (%) 4.19 Lysine (Dig) (%) 0.66

Crude Fibre (%) 4.39 Methionine (Dig)(%) 0.39

Ash (%) 11.36

Methionine+Cystine

(Dig)(%) 0.59

Calcium (%) 3.2 Linolenic acid (Dig) (%) 1.64

Phosphorus

(Available) (%) 0.3 - -

1Provided the following per kilogram of diet: vitamin A (as retinyl acetate), 8.8 (TIU);

cholecalciferol, 3.3 (TIU); vitamin E (as dl-α-tocopheryl acetate), 44 IU; vitamin B12,11

mg; riboflavin, 8.8 mg; d-calcium pantothenic acid, 15.5 mg; niacin, 53 mg; choline, 660

mg; folic acid, 1.0 mg; vitamin B1 (thiamin mononitrate), 4.4 mg; pyridoxine, 3.3 mg;

biotin, 0.22 mg; vitamin K (menadione sodium bisulfate complex), 3.3 mg. 2Provided the following per kilogram of diet: manganese sulphate, 211.6 mg; copper

sulphate, 23 mg; zinc sulphate, 195 mg; selenium, 0.3 mg;potassium iodide, 2.4 mg

Table 3.2: The plan to study the effect egg weight and age on egg quality

parameters in broiler breeder

77

Major

treatment

(Flock age)

Sub treatment

(Egg category)

No of replicate

per sub

treatment

*Eggs per

replicate

Total egg

per sub

treatment

A

(30 week)

AA

(Low Weight)

10 1 10

AB

(Medium weight)

10 1 10

AC

(Heavy weight)

10 1 10

B

(45 week)

BA

(Low Weight)

10 1 10

BB

(Medium weight)

10 1 10

BC

(Heavy weight)

10 1 10

C

(60 week)

CA

(Low Weight)

10 1 10

CB

(Medium weight)

10 1 10

CC

(Heavy weight)

10 1 10

*Each egg was considered as a single replicate

following formula

Yolk weight (%) = (Yolk weight (g)) / (Egg weight (g)) ×100

78

3.3.3.5 Albumen Weight

All the 10 eggs of each egg weight category were broken open. Albumen

weight was calculated by subtracting the weights (yolk weight+ shell weight+ shell

membranes weight) from individual egg weight to measure albumen weight

percentage by the following formula

Albumen weight (%) = (Albumen weight (g)) / (Egg weight (g)) ×100

3.3.3.6 Yolk to Albumen Ratio

From the yolk and albumen weights, yolk to albumen ratio in percentage was

calculated by following formula

Yolk to albumen ratio (%) = (Yolk weight (g)) / (Albumen weight (g)) ×100

3.3.3.7 Shape Index

The short and long diameters of all the 10 eggs of each egg weight category

were measured by a digital caliper with a sensitivity of 0.001 mm to measure the

shape index by the formula as shown below

Shape index = short edge/long edge × 100

(Yannakopoulos and Tserveni- Gousi, 1986)

3.3.3.8 Egg Specific Gravity

The egg specific gravity is an index of shell thickness and porosity. In this

experiment 10 eggs from each egg category were selected to measure specific gravity

on the day of laying. Each egg was weighed in air on a Mettler scale (model

# BD601) individually and then in water by same scale. The temperature of the water

was kept at 23 °C during experiment. The egg specific gravity of each egg was

measured by the Archi-medes method using formula as described by Hampe

et al. (1988).

Specific gravity = weight in air (g)/ [weight in air (g) − weight in water (g)].

79


Data were evaluated using Two-way ANOVA and analyzed using GLM

(General Linear Model) procedures of SPSS 16.0 software. When differences were

significant, means were compared using Duncan’s Multiple Range tests at the 0.05

level of significance.


3.4.1 Influence of Egg Size on Egg Quality Characteristics

The effect of egg size on egg quality characteristics (shell weight, shell

thickness, yolk weight, albumen weight, egg yolk to albumen ratio, egg shape index

and egg specific gravity) in broiler breeder at early (30 week) stage of production

period is shown in Table 3.3. At this production stage, an average egg weight of

small, medium and large eggs were 51.46, 56.48 and 61.41 g, respectively. Egg size

had non-significant (p≥0.05) effect on all egg quality parameters (shell weight, shell

thickness, albumen weight, yolk weight, yolk to albumen ratio, shape index and

specific gravity) was observed.

The influence of egg size on egg quality characteristics (shell weight, shell


and egg specific gravity) in broiler breeder at mid (45 week) stage of production

period is given in Table 3.4. At mid stage of production period, an average egg weight

of small, medium and large eggs were 60.25, 65.10 and 70.07g, respectively. Egg

size had significant (p≤0.05) effect on shell weight, shape index and specific gravity

at mid stage of production period. In general, it was observed that shell weight, shape

index and specific gravity diminished with increasing the egg size. Maximum shell

weight percentage, shape index and specific gravity (p≤0.05) was evidenced in small-

sized egg group (9.99%, 76.34 and 1.078, respectively), followed by medium

(9.62%, 75.84 and 1.074, respectively) and large (9.42 %, 74.81 and 1.070,

80

respectively) egg size groups. In this trial, specific gravity measurements have shown

to decrease significantly after 45 weeks of production cycle. Non-significant

(p≥0.05) effect of egg size was observed on shell thickness, yolk weight, albumen

weight and yolk to albumen ratio at mid stage of production period in Hubbard broiler

flock.

The influence of egg size on egg quality characteristics (shell weight, shell


and egg specific gravity) in broiler breeder flock at late (60 week) stage of production

period are presented in Table 3.5. At late stage of production cycle, an average egg

weight of small, medium and large weights eggs were 63.43, 69.15 and 75.05 g,

respectively. Egg size had significant (p≤0.05) effect on shell weight, shell thickness,

shape index and specific gravity at late stage of production period. Overall, it was

examined that shell weight, shell thickness, shape index and specific gravity reduced

with increasing the egg size. Maximum shell weight percentage, shell thickness,

shape index and specific gravity (p≤0.05) was achieved in smallsized egg (9.49%,

0.34mm, 74.64 and 1.068, respectively), followed by medium (9.05%, 0.33mm,

73.81 and 1.065, respectively) and large (8.82%, 0.32mm, 73.00 and 1.059,

respectively) sized egg groups. Non-significant (p≥0.05) effect of egg Table 3.3:

Effect of egg size on egg quality characteristics in hubbard broiler

breeder at early (30 week) stage of production period (Means± SE)

Parameters Egg size

SEM P-

Value Small Medium Large

Egg weight (g) 51.46a±0.15 56.48b±0.14 61.41c±0.18 0.759 0.000

Shell weight (%) 10.52±0.14 10.46±0.13 10.13±0.14 0.082 0.122

Shell thickness

(mm) 0.37±0.004 0.37±0.004 0.36±0.008 0.003 0.396

Yolk weight (%) 29.06±0.24 29.30±0.14 29.54±0.16 0.103 0.182

81

Albumen weight

(%) 58.53±0.18 58.67±0.21 59.00±0.14 0.105 0.167

Yolk to albumen

ratio (%) 49.67±0.54 49.95±0.40 50.28±0.34 0.247 0.619

Shape index 78.21±0.48 77.80±0.78 76.54±0.44 0.351 0.127

Specific gravity 1.087±0.001 1.087±0.001 1.085±0.001 0.001 0.670

a-c Means with different letters in rows differ significantly (

Table 3.4: Effect of egg size on egg quality characteristics in hubbard broiler

breeder at mid (45 week) stage of production period (Means± SE)

Parameters

Egg size

SEM P-


Egg weight (g) 60.25a±0.25 65.10b±0.31 70.07c±0.61 0.781 0.000

Shell weight (%) 9.99a±0.19 9.62ab±0.15 9.42b±0.14 0.101 0.062

Shell thickness

(mm) 0.35±0.00 0.34±0.00 0.34±0.00 0.00406 0.232

Yolk weight (%) 30.79±0.34 31.13±0.27 31.57±0.48 0.21734 0.346

82

Albumen weight

(%) 57.80±0.47 58.07±0.25 57.98±0.45 0.2245 0.889

Yolk to albumen

ratio (%) 53.30±0.98 53.63±0.67 54.54±1.24 0.516 0.661

Shape index 76.34a±0.62 75.84ab±0.36 74.81b±0.40 0.2892 0.086

Specific gravity 1.078a±0.00 1.074b±0.00 1.070c±0.00 0.000 0.000

a-c Means with different letters in rows differ significantly (

Table 3.5: Effect of egg size on egg quality characteristics in hubbard broiler

breeder at late (60 week) stage of production period (Means± SE)

Parameters Egg size

SEM P-


Egg weight (g) 63.43a±0.25 69.15b±025 75.05c±0.16 0.8905 0.000

Shell weight (%) 9.49a±0.19 9.05b±0.15 8.82c±0.12 0.101 0.017

Shell thickness

(mm) 0.34a±0.00 0.33ab±0.00 0.32b±0.00 0.002 0.024

Yolk weight (%) 33.69±0.18 33.77±0.16 34.16±0.17 0.103 0.149

Albumen weight

(%) 55.57±0.24 56.13±0.26 56.43±0.40 0.18479 0.156

83

Yolk to albumen

ratio (%) 60.65±0.54 60.19±0.55 60.98±0.53 0.30706 0.586

Shape index 74.64a±0.38 73.81ab±0.38 73.00b±0.40 0.226 0.008

Specific gravity 1.068a±0.00 1.065a±0.00 1.059b±0.00 0.000 0.000

a-c Means with different letters in rows differ significantly (P≤ 0.05)

size was observed on yolk weight, albumen weight and yolk to albumin ratio at late

stage of production period in broiler breeder.

There is a paucity of literature on the effect of egg size on egg quality

parameters. The egg shell not only provides the protection to egg contents against

dehydration, mechanical impact, and microorganism contamination but it is also

permeable to water and gases necessary for the chick embryo development

(Rodríguez-Nav et al., 2013). The present study showed that small-sized eggs had

more shell weight percentages than medium and large-sized egg category at early,

mid and late stage of production cycle. These results are concurred with the findings

of Shafey (2002), who reported that small-sized eggs had more (p≤0.05) egg shell

weight percentage (14.1%) as compared to medium (12%) and large

(11.5%) egg-sized groups in meat and layer breeders at the 42 to 46 weeks of age.

He also reported that egg size had no effect on shell thickness (0.33, 0.35 and 0.34

mm for small, medium and large egg size groups, respectively. These values are very

84

close to the present study at the mid (45 weeks) stage of production period which

also showed non-significant (p≥0.05) difference of egg size on shell thickness.

However, Şekeroǧlu and Altuntaş (2009) reported that egg shell thickness was

highest (p≤0.05) in medium-sized egg (0.400 mm) and lowest in extra-large size egg

(0.382 mm) in brown egg layer strain of Lohmann. Similar trend was observed in the

present study, lowest value of this trait was found in large-sized egg group during

throughout the production period. Regardless the egg size, the weight of the egg shell

was about 9.72% of egg’s weight in the present study. Whereas, Popova-Ralcheva et

al. (2009) reported that egg shell weight was only 12% of egg’s weight and shell

thickness was an indirect index of its strength.

In broiler breeder, the normal egg shell thickness is about 0.30-0.34 mm

(PopovaRalcheva et al., 2009) which is close to value of the current study.

The data obtained on improved (p≥0.05) in the albumen weight with

increasing in egg size in this study corroborate the findings of Finkler et al. (1998),

who observed that there is an increase in the albumen weight with increase of egg

size. Such correlation may confound tests of the relative influence of each egg

component on the mass and composition of the embryo. Hence, egg size influences

the weight of its components. Shi et al. (2009) reported that albumen weight

percentage increased with egg size increasing in brown egg layer strain of Nike.

There was significant positive correlations between egg size and albumen weight

percentage. Similarly, in this trial, albumen weight was also increased with egg size

increasing but difference was non-significant during throughout the production cycle.

Recently, Egbeyale et al. (2013) reported that albumen and yolk weight in Dominant

Black strain of pullet eggs was found as 53.79, 56.09 and 58.37%; 32.50,

26.46 and 28.14% for small, medium and large-sized egg groups, respectively.

Similarly, these traits in Yaffa Brown strain of pullet eggs was examined as 50.33,

55.0 and 60.67%; 29.85, 25.45 and 27.98% for small, medium and large egg size

85

groups, respectively. The data showed that in both strains, egg albumen weight

increased with increase the egg size and reverse trend was observed in yolk weight.

While in this study, albumen and yolk weight both increased with increasing the egg

size might be due to breed difference from above study.

Egg shape index, which can be easily described in terms of the ratio of the

maximum breadth and length that vary according to egg size, strain, position of the

egg in clutch (Romanoff and Romanoff, (1949) and time of oviposition (Roland,

1978). King, ori, (2012) reported that shape index increased until the 20 or 24 weeks

of production then decreased gradually. Similarly, in the present study, shape index

values were decreased during early, mid and late stage of production cycle. Eggs laid

during the second year of production have significantly lower shape indices than eggs

laid in the first year of production (Muller et al., 1960). In the current study, second

year production data was not recorded. Egg shape is also influenced by genetic

factors and individual traits. In birds, the egg shape index ranges between 57 and 92

but below than 74 is a major cause for higher incidence of cracked and broken eggs

(Narushin et al., 2004; Narushin, 2005). In this experiment, values of egg shape were

found ranged 73 to 78.21 which are considered as normal values.

Egg specific gravity is an indirect presentation of the quantity of shell present

in relation to the size of the egg. Thus the egg specific gravity is an index of shell

thickness and porosity (Hamilton 1982). No literature is available on effect of egg

size on specific gravity of hatching eggs in breeders.

It is concluded that egg weight increased with progressing the production

cycle. The values of shell weight, shell thickness, shape index and specific gravity of

hatching eggs were decreased with increasing egg size. Percentages of yolk and

albumen weight were increased with increasing the egg size.

86

3.4.2 Influence of Age on Egg Quality Characteristics

The influence of age on egg quality characteristics (shell weight, shell


and egg specific gravity) in broiler breeder flock are shown in Table 3.6. The results

showed that egg weight was found increased (p≤0.05) with advancing of Table 3.6:

Effect of age on egg quality characteristics in hubbard broiler breeder

(Means± SE)

Parameters

Age (weeks)

SEM P-

Value 30 45 60

Egg weight (g) 56.45a±0.76

65.14b±0.78 69.21c±0.89 0.730 0.000

Shell weight (%) 10.37a±0.00

9.68b±0.10 9.12c±0.10 0.077 0.000

Shell thickness

(mm)

0.37a±0.00 0.35b±0.00 0.33c±0.00 0.003 0.000

Yolk weight (%) 29.30a±0.11

31.16b±0.22 33.82c±0.13 0.214 0.000

Albumen weight

(%)

58.72a±0.10

57.95b±0.22 56.08c±0.20 0.155 0.000

Yolk to albumen

ratio

49.91a±0.25 53.82b±0.56 60.48c±0.37

0.512 0.000

Shape index 77.51a±0.35

75.66b±0.29 73.82c±0.23 0.232 0.000

Specific gravity 1.0864a±0.00

1.0738b±0.00 1.0642c±0.00 0.001 0.000


87

breeder age as 56.45, 65.14 and 69.21 g at 30, 45 and 60 weeks of age, respectively.

Similarly, yolk weight percentage and yolk to albumen ratio were also improved

(p≤0.05) with advancing of age. However, shell thickness, albumen weight, shape

index and specific gravity were reduced (p≤0.05) with advancing of breeder age.

These results are in line with findings of Gualhanone et al. (2012), who reported that

egg weight of Cobb broiler breeder was increased at 30 week (59.48g) to 60 week

(70.39g) of age. Many other studies also showed that egg weight increased with the

breeder age and older breeders with heavier eggs produced heavier chicks (North and

Bell, 1990; Suarez et al., 1997; Novo et al.,

1997; Adamski, 2008). Tona et al. (2004) observed that the weight of eggs laid by

Cobb hens aged 35 and 45 weeks was 66.44 and 70.56 g respectively, and it was

higher than in our experiment. This increase in egg weight with age was due to the

increasing weight of the yolk rather than white, whose proportion in the egg mass

decreased.

Age has also effects on internal egg and eggshell quality characteristics

(O’Sullivan et al., 1991; Benton and Brake, 1996; Latour et al., 1998). It has been

shown in previous studies that the egg shell thins with age (Roland, 1976) and the

eggs from the young hens had generally thicker shells than those from older hens

(Britton, 1977; Peebles and Brake, 1987). Recently, Kontecka et al. (2012) also

reported that shell weight (%) and shell thickness were higher in the 26 th than in the

56th week of Cobb broiler breeder age as in case of the present study. Similar results

were reported in quail breeder, earlier studies conducted by Yannakopoulos and

Tserveni‐Gousi (1986), who suggested that egg weight, yolk index increased,

88

whereas the egg shape index and shell thickness decreased with the advancement in

age of Japanese quail. Other studies also concluded that as the quail age increased

yolk, albumen and shell weight also improved, while shell thickness reduced (Rizzi

and Chiericato, 2005; Johnston and Gous, 2007; Hussain et al., 2011).

In the present study, percentages of egg yolk increased and albumen

decreased with age. These results are agree with the findings of Ahn et al. (1997) and

Suarez et al. (1997), who reported that eggs laid at 29 week of age had less yolk and

greater albumen percentages than those laid at 59 week of age. These workers also

explained that that the egg yolk fulfills the nutrient requirements of the growing

embryo. Silversides and Scott (2001) reported that egg size increased with the age of

the hen, and the yolk increased more in size than did the shell and albumen. Pirsaraei

et al. (2011) found that eggs from older broiler breeders (58 week) were characterized

by higher yolk weight and lower white weight, by 1.25 g on average as compared

with birds in the initial period of egg laying (22 week of age). Traldi et al. (2011)

reported that egg yolk weight at 29 and 55 weeks of Ross broiler breeder age was

found as 26.67 and 32.64%, respectively. However, egg albumen weight at the same

age was recorded as 59.82 and 55.25%, respectively. Almost similar values and trend

was noticed in the present study. Recently, Kontecka et al. (2012) reported that

albumen percentage was decreased with advancing reproductive period (65.41% at

26 week and 61.11% at 56 week of Cobb broiler breeder age). Similar trend was

observed in the present study, albumen percentage was found as 58.72% at 30 week

and 56.08% at 60 week of age.

As the age of broiler breeders under investigation advanced, the egg shape

index decreased significantly, i.e. the eggs became more elongated. Adamski (2008)

proved a reverse trend in Hubbard Flex hens. Over 39 weeks of production, it was

observed a positive trend-cycle of this characteristic, where the directional factor was

0.16. On the other hand, some researchers did not provide clear results concerning

89

changes in the egg shape during the reproductive cycle of other poultry species

(González, 1995). However, the egg weight seems to be of key importance, because

as it increases, the shape index decreases, i.e. eggs become more elongated

(Nowaczewski et al., 2010). This fact is also confirmed by the observations of

negative coefficients of correlation between those characteristics (Kul and Seker,

2004; Nowaczewski et al., 2008). In recent, Kontecka et al. (2012) reported that the

values of egg shape index of hatching eggs of Cobb 500 broiler breeders were

reduced as the reproductive period progressed (76.4 to 72.9 from 26 to 56 weeks of

age). These values are very close to current study i.e. 77.51 to 73.82 from 30 to 60

weeks of age. Different scientists (Monira et al., 2003; Brand et al., 2004) reported

negative correlation between the age and egg shape index, it might be due to the fact

that as age increases eggs become longer than wider and egg shape index is directly

proportional to the egg breadth.

The egg specific gravity is possibly a good indicator of the shell quality. In

the poultry industry, the specific gravity is mostly used to measure shell quality of

eggs. As the hen ages or during periods of stress the specific gravity (shell quality)

of eggs is affected. The current research revealed successive and significant reduction

in the egg specific gravity as the reproductive period progressed. These results are

confirmed by the findings of Pirsaraei et al. (2011), who compared egg specific

gravity in Ross 308 hens aged 22, 34, 48 and 58 weeks. The data did not observe

statistically significant differences and the value of this trait ranged between 1.065

and 1.075. Whereas, in this study, range values of this trait was found between 1.086

and 1.064 at aged from 30 to 60 weeks. Amem and Al-Daraji (2011) also reported

same trend that the values of specific gravity at the age of 54, 58 and 62 weeks old

broiler breeder hens were found as 1.081, 1.077 and 1.060, respectively. Gualhanone

et al. (2012) reported that specific gravity in hatching eggs of Cobb broiler breeder

was found decreased at 30 week (1.084) to 60 week (1.082) of age. In the present

90

study, more values of specific gravity were reduced at the same age (1.086 to 1.064)

as compared to above study. Recently, Kontecka et al. (2012) also reported that the

values of egg specific gravity of hatching eggs of

Cobb 500 broiler breeders were reduced as the reproductive period progressed (1.08

to 1.070) from 26 to 56 weeks of age). These values are very close to the current

study i.e. 1.08 to 1.06 from 30 to 60 weeks of Hubbard broiler age. The egg specific

gravity and egg shell thickness decrease with advancing breeder age (Dohnal et al.,

1986; Szczerbińska, 1996). This occurred basically due to the egg size increased

more quickly than the shell weight (Butcher et al., 1991) and

because there was an increase in egg size rather than calcium deposition in the egg

shell (Curtis et al., 1985).

It may be concluded that as the reproductive period of broiler breeders

progressed, the weight of their eggs increased. This fact was mainly due to the

increasing yolk weight, because its percentage in the egg mass increased with bird

age, whereas the percentage of the white decreased. Egg shell weight was improved

with advancing hen age. The other factors like shell thickness, shape index and

specific gravity of hatching eggs was proved to be significantly lower with advancing

of age.

Chapter 4

EFFECTS OF EGG SIZE (WEIGHT) AND AGE ON HATCHING

PERFORMANCE AND CHICK QUALITY OF BROILER

91

BREEDER

4.1 INTRODUCTION

Poultry production is the main source of household nutrition and income in

the country. Most of the poultry in the country is exotic breeds such as the Hubbard

chickens. Although broiler farming is running at commercial level, however, limited

information exists on the effect of the hatching egg size and breeder age on hatching

performance of Hubbard broiler chickens. This implies that their contribution to the

household protein food security may not be fully realized without appropriate

management and husbandry interventions as suggested by many workers (Abiola,

1999; Donald et al., 2002; Rashid et al., 2005; King’ori et al., 2007), who reported

that performance in chickens in terms of hatchability and chick-hatch weight may be

closely related to the weight of the eggs because the influence of egg size mainly lies

in the mass of the residual yolk sac that the chick retains at hatching. King'ori (2011)

suggested that chick weight, fertility and hatchability are interrelated heritable traits

that vary among breeds, variety or individuals in a breed or variety; therefore it

becomes very important to understand the effect of egg size on these traits in Hubbard

broiler chickens. Egg size has been widely studied in the life history of the birds

because it can be highly variable. In the production periods of the broiler breeder, the

hen begins to lay small eggs and after few weeks of production, go to lay desired

medium sized eggs and then to the

66

extra-large sized eggs at the termination of production cycle. Although egg size can

be manipulated by using the various levels of fat, protein or enzymes in poultry feed,

but some other factors such as body weight and age of the hen, nutrient intake and

yolk weight could also influence egg size. Asuquo and Okon (1993) studied the

92

effects of egg size and age on fertility and hatchability of eggs in broiler breeder.

These workers noticed that egg size within the range of 45-56 g always hatch better

than small or large sized eggs. No biological reasons were suggested for such an

observation.

Some studies showed that the reproduction efficiency of the broiler breeders

decreased with age, as it is related to the quality of hatching egg such as poorer shell

quality, larger egg weight, increased early and late embryo mortalities, variations in

the internal egg composition or ratio and some other problems related with large eggs

from old broiler breeders (Elibol and Brake, 2003; Tona et al.,

2004; Joseph and Moran, 2005). Broiler breeder age (O’Sullivan et al., 1991; Latour

et al., 1996; Peebles et al., 2001) influenced subsequent embryonic development and

hatchability of broiler breeder hatching eggs. Fertility of an egg and embryonic

deaths during the incubation process are different for different broiler breeder strains.

Deeming and Van Middelkoop (1999) reported that as the flock ages, there was more

early embryonic deaths and infertility in the eggs from Ross 308 compared with Cobb

500. It is well recognized that there is a strong relationship between breeder age and

egg weight such that older hens produce larger eggs (Lourens et al., 2006). Chick

weight increased with advancing age of broilers’ breeders as reported by Yildirim,

(2005) and Christensen et al. (2002).

However, in past research, egg size and broiler breeder age are always linked

together. Wyatt et al., (1985) showed that egg weight increases with flock age. There

is a limited research work showing the separate effects of egg weight and flock age

on broiler chick quality. Extensive research has not been done to determine the effect

of egg size and age on fertility, hatchability traits and chick quality in commercial

Hubbard Classic broiler breeder strain.

The objective of this trial was to study the effects of egg size (small, medium

and large) and flock age (30, 45 and 60 weeks old) independently of each other and

http://www.sciencedirect.com/science/article/pii/S1658077X12000252#b0100






93

to evaluate the effect of these factors on hatching egg weight loss during incubation,

fertility, hatchability traits, day-old chick’s weight, chick yield, sex yield and chick

quality in a most popular commercial Hubbard Classic broiler breeder strain in

Pakistan.


4.2.1 Hatchability

Hatchability is one of the most important economic performance

indicators of broiler hatching egg industry. Hatchability (the number of chicks

hatched out of incubated eggs) is affected by several management factors. A number

of factors including egg age, storage conditions, age of flock, system of husbandry

and rearing technology, health status of birds, mating system, egg turning angle and

frequency, incubation temperature and relative humidity have been shown to

influence the fertility and hatchability of poultry eggs.

4.2.2 Effect of Egg Size (Weight) of Broiler Breeder on Hatchability

In the life history of poultry, egg size has been widely studied as it is highly

variable trait. Mbajiorgu (2011) studied the relationship between the egg size and

hatchability of indigenous Venda chicken and found that medium size eggs produced

chicks with significantly (p≤0.05) higher hatch weight as compared to small or large

size eggs. He further concluded that maximum hatchability achieved at hatching egg

weight of 67 g. His conclusions further showed that the egg weights for optimum

hatchability and optimum hatched chick’s weight were different in indigenous Venda

chickens. However, the values of optimum hatchability and hatched chick’s weight

obtained were 67 g and 60 g that were higher than the average egg weight of 52.81g

in this study. Finally, he concluded that improvement in egg size in indigenous Venda

chickens would be to maximize the hatchability and chick’s hatch weight.

94

Wilson (1991) reported that hatchability has very low heritability.

Improvement in hatchability by selection takes a long time to achieve desired results,

so optimization of hatching egg weight, broiler breeder farms and hatchery

managements are the most important for improvement. In the same study, he

concluded that large size eggs had better hatchability value as compared to medium

and small-sized eggs. He further suggested that the incubation of egg size group (60

to 69 g) was best for maximum hatchability. Contrary to Wilson (1991) finding,

Kalita (1994) reported higher hatchability percentage for medium-sized eggs when

compared to too small or too large eggs. Similarly Abiola et al. (2008) conducted a

study to evaluate the effect of egg size on hatchability. A total of 198 hatchable Anak

broiler eggs comprising of small (40 g average weight), medium (50 g average

weight) and large (60 g average weight) size categories were obtained from a

commercial hatchery for the study .Results obtained on hatchability of eggs did not

follow any particular trend. However, values obtained were ranging between 82.88

and 96.67%. Best result of 96.67% hatchability was obtained for medium eggs while

large eggs had the lowest value of 82.88%

hatchability.

4.2.3 Effect of Age of Broiler Breeder on Hatchability

Wolc et al. (2010) conducted a study to evaluate the genetic basis of

variability of hatchability in broiler breeders with age and the results by using a

longitudinal model. Collected weekly data of hatchability as well as of set eggs from

a flock of 23,250 breeder hens and 3,106 males between 28 and 54 week of age

showed that hatchability of set eggs was highly correlated with fertility throughout

laying period. The hen had a genetic contribution for hatching of fertile eggs and its

heritability from peak lay onward was about 6% but low earlier. Abudabus (2010)

studied the effect of genetic strain Ross 308 aged 32-36 weeks and Cobb 500 aged

95

26-44 weeks on hatchability and fertile hatchability. At the above mentioned flock

ages, 300 eggs from each treatment group were incubated. He observed lowest

hatchability among all groups was (70.4%) from eggs from the oldest group (Ross

44) but the average estimated hatchability increased to 85.2% for the younger group

of the same strain. He further investigated nonsignificant difference in hatchability

for Ross strain at 32 and 36 week of age. He also observed that fertile hatchability

was higher at any age of production periods.

Fertile hatchability percentages differed between treatments and were 92.2, 85.2,

97.7 and 94.1% for Cobb 26, Cobb 44, Ross 32 and Ross 36 respectively. Infertility

was affected by age and higher infertile eggs (14.8%) were obtained from eggs from

the oldest group (Cobb 44 weeks) followed (7.8%) by eggs from Cobb 26, (p < 0.05).

Ross at 32 week had the lowest percentage of infertile eggs (3.3%).

Mustafa et al. (2010) conducted a study to determine hatchability of fertile

eggs in the hatching eggs of Lohmann brown hybrid and Arbor Acres white birds at

different ages of production period. They observed that the ages (24, 30, 35, 40, 50,

55, 60 and 65 weeks) had significant (p≤0.05) effect on the fertility and hatchability

traits. They further observed that fertility and hatchability of total eggs were

increased significantly (p≤0.05) from 24 to 45 week of age and then decreased from

50 to 65 week of age. In another study conducted by Kirk et al. (1980) it was also

observed that with the increase in age fertility and hatchability were decreased. In

this study at 60 week of age (post-peak broiler breeders), fertility and hatchability

were declined by 11 and 9% respectively, in eggs weighing more than 70 g. They

further concluded that younger broiler breeders produced eggs with superior

hatchability at an average weight of 60 g but the older broiler breeders (60 week)

produced eggs with low fertility and hatchability. On contrary to these results, Ulmer-

Franco et al. (2010) studied the effect of age on fertility and hatching time and

96

observed low fertility for 29 week old flock as compared to 59 week flock. He further

observed that chicks from 59 week old flock hatched earlier than 29 week. He also

concluded that lighter eggs hatched earlier when compared to average or heavy eggs

at same age of broiler breeder flock.

Rouqe and Soares (1994) assessed the effects of age and egg shell quality on

fertility and hatchability in broiler breeder. In the trials, hatching eggs were obtained

from three commercial broiler breeder flocks at different ages but of the same strain.

The hatching eggs according to specific gravities were distributed in to two groups,

thin-shelled (SG<1.080) and thick-shelled (SG>1.080). Thickshelled eggs showed

better hatchability than that of thin-shelled eggs because of greater fertility. They

further concluded that hatchability and viability (hatchability of fertile eggs) were

lower in the younger flock because of higher early and late embryonic mortalities

during incubation process.

Female fertility can affect the number of chicks hatched as unfertile eggs (do

not produce chicks). An excessive intake of nutrients resulted in obese hen that

decreased fertility due to a decrease in hen ability to store and transport sperm cells

as a consequence of fat blockage of storage tubules (Mc Daniel et al., 1981).

4.2.4 Effect of Egg Size (Weight) and Age of Broiler Breeder on Egg

Weight Loss Percentages during Incubation

In fertile eggs, water is lost by evaporation that is determined by the storage

and incubation conditions and duration and the surface and porosity of the shell

(Sauveur, 1988). Baggott (2001) studied that in most chicken species, 20% total

water is lost in relation to initial egg mass which results a similar water concentration

both in chick and egg. He further concluded that during incubation 28.60 and 07.20

grams of water were disappeared from the albumen and yolk respectively.

Furthermore, 24.70 g in the embryo’s body tissue and 2.50 g of water in the residual

97

yolk were observed. Thus balance of water was -08.60 grams. Similar values were

described by Sauveur (1988) who reported that 08.54 and 10.31 grams of water

produced during 18 and 21 days of incubation respectively. Meijerhof

(2009) studied that during incubation, metabolic water represents 12-14% of the

setting egg weight and at least 9 to 10% water loss is necessary to create an air space

sufficient to facilitate pulmonary respiration.

Tona et al. (2001) reported that maximum numbers of day-old chicks were

hatched out of fertile eggs when cumulative water loss during incubation varied

between 10.9 and 11.1%. They further observed that higher egg weight loss leads to

fewer hatch problems as compared to lower water loss. They also observed a direct

relation between the flock age and water loss. When the egg weight loss before

internal pipping was less than 6.5%, the resultant air cell size was insufficient to

engage pulmonary respiration. Inversely, for more than 14.0% egg weight losses,

the risks of dehydration were increased (Molenaar et al., 2010). According to

Meijerhof (2009), risks of dehydration appeared when losses were close to 17-18%.

The fact remains that egg weight loss during incubation is only dependent on the

shell conductance and ambient humidity. No other factor was involved. As shell

conductance of every egg is different and it is better to use margin for loss rather than

using an optimal loss.

Abiola et al. (2008) conducted an experiment to determine the effect of egg

size on egg weight loss percentages. A total of 198 hatchable Anak broiler eggs

comprising of small (40 g average weight), medium (50 g average weight) and large

(60 g average weight) size categories were obtained from a commercial hatchery for

the study. Although values obtained on egg weight loss for the 3 size categories were

comparable with one another, lowest egg weight loss of 11.24% was obtained for

large eggs while highest egg weight loss of 11.57% was recorded for medium eggs.

98

Abudabus (2010) studied that the effect of hen age (within the strain) on egg

weight loss was non-significant (p≥0.05). He further observed that egg weight loss

(EWL) for Ross strain was significantly higher than those from Cobb strain (p≤0.01)

at 7, 14 and 19 day of incubation and as a result, the total EWL from 1-19 day was

significantly higher (p≤0.001) for Ross strain.

Mc Daniel et al. (1979) determined the effect of specific gravities on egg

weight losses in broiler breeder hens at 36, 52 and 64 weeks of age. Eggs were

collected at 2-hour intervals and specific gravities were determined on the day of

laying. Egg weights were recorded prior to specific gravities determination, at setting

and transfer to hatcher, to establish weight losses during incubation. Results showed

that there were maximum weight losses in the eggs having lowest specific gravities

and vice versa. Reis et al. (1997) compared the egg weight losses due to evaporation

between larger eggs (from post-peak broiler breeder) and smaller eggs (from young

broiler breeder). They concluded that less water loss in large sized eggs may be

explained, as l less shell area per unit of interior egg weight in larger eggs compared

to smaller eggs (Kirk et al., 1980).

Rouqe and Soeres (1994) studied the effects of age and shell quality on egg

weight loss percentages in broiler breeders. For this objective, they obtained hatching

eggs from 3 commercial flocks of different ages but of the same strain. The eggs

were distributed into two groups according to specific gravities, thinshelled

(SG<1.080) and thick-shelled (SG>1.080). They concluded that thinshelled eggs had

a greater increase in weight with age and showed a greater percentage of egg weight

loss during incubation at all stages of production cycle. They also observed that eggs

from the younger flocks showed a higher weight loss percentage during incubation

irrespective of shell thickness because of smaller egg size.

4.2.5 Effect of Egg Size (Weight) and Age of Broiler Breeder on Embryo

99

Death during Incubation and Pipped-not-Hatched Egg

There are three phases of embryonic death: early, middle and late. The early

embryonic death phase represents eggs that die during the first week of incubation.

This embryonic death is a result of failure of the development of embryo either during

storage or when placed in the setter (North and Bell, 1990). The mid embryonic

death phase represents the eggs that die during second week of incubation. The

nutritional deficiencies in the broiler breeder diet are mainly responsible for mid

phase embryonic death. The late embryonic death phase represents the eggs that die

during the 3rd week (last week) of incubation. Complications in physiological

changes of developing embryo, abnormal positioning, and some lethal genes are

main causes of last phase of embryonic death (Tullet, 2009).

French (1997) conducted a study to observe the effect of incubator (machine)

temperature on hatchability of large and small sized eggs. During the first half of

incubation (early embryonic developments) the hatching eggs are endothermic and

exothermic during the second half of incubation (late embryonic developments).

Consequently, it has been observed that larger eggs produce more heat (during

exothermic phase of fertile eggs) when compared with small eggs. This higher

incubation temperature during the last half of incubation due to large egg size is

responsible for reduction in hatchability (because of increased embryonic deaths).

Finally, he concluded that lowering of incubation temperature during the last week

of incubation for the large size eggs results in good hatchability. Furthermore,

Lourens et al. (2005) concluded that fluctuations in machine temperature during

incubations of fertile eggs results in lower hatchability. This observation was further

confirmed by Yalcin and Siegel (2003) who examined the impaired lung

development in the growing embryos exposed to cold and heat phases during

incubation period.

100

North and Bell (1990) conducted a study to observe the effect of frequency

of egg collection from breeder layer house on embryo development and successful

hatching. They concluded that hatching eggs should be collected at the farm more

than four times a day for better hatchability. It is necessary to collect eggs as early

as possible to prevent pre-incubation of the hen, which result in decreases in

uniformity of hatching time and affect hatchability. This investigation was further

supported by Meijerhof (1992) who studied that the stage of embryonic development

at the oviposition affects the hatching results. Parkhurst and Mountney (1988) studied

that embryo at oviposition has a chronological development age of approximately

24-26 hours.

Mather and Laughlin (1979) observed the different embryo sizes at

oviposition and explained that differences may be the result of the duration of time

the egg is retained within the oviduct. They also found that the blastoderm area in

fresh non-incubated eggs increases with parental age. These observations were

further supported by Crittenden and Bohren (1962) who observed that eggs laid by

post-peak broiler breeders had advanced embryonic development, which may result

in earlier hatching time. Coleman and Siegel (1966) conducted a study and concluded

that stage of embryonic development (embryo size) at oviposition is correlated with

body weight of hen. They also reported, hatching eggs produced by the hens that had

low body weight at 8 weeks of age, had embryo with advanced development at

oviposition which results in higher hatchability in broiler breeder.

Abudabus (2010) studied the effect of genetic strain Ross 308 aged 32-36

weeks and Cobb 500 aged 26-44 weeks on egg break out analysis. At each flock age,

300 eggs from each treatment group were incubated. He concluded that age or strain

had non-significant (p≥0.05) effect on early and late death of the embryo but mid

death embryo were higher (p≤0.01) in older flocks. Pipped not hatched percentage

101

was higher (p≤0.01) for eggs from Ross strain at 32 week and Cobb 500 at 26 week

of age and in older flocks. Similarly Mustafa et al. (2010) studied the significant

effects (p≤0.05) of ages (24, 30, 35, 40, 50, 55, 60 and 65 weeks) on embryonic

mortality in the hatching eggs of Lohmann brown hybrid and Arbor Acres white

birds.

Rouqe and Soeres (1994) studied the effects of age and egg shell quality on

embryonic mortality, culled chicks and pipped not hatched chicks. For this study

hatching eggs were obtained from three broiler breeder flocks of the same strain at

different weeks of age. They distributed the eggs into two groups according to

specific gravities, thin-shelled (SG<1.080) and thick-shelled (SG>1.080). They

observed that thick-shelled eggs resulted in low intermediate and late embryonic

deaths when compared to thin-shelled eggs at different ages but the percentage of

culls, pips and rots were not affected by shell thickness. They also observed lower

hatchability and hatchability in younger flocks because of higher early and late

embryonic deaths. They also investigated that broiler breeder age had no effect on

culled chicks and pipped-not-hatched eggs.

4.2.6 Effect of Egg Size (Weight) and Age of Broiler Breeder on Chick Yield

(Chick to Egg Weight Ratio)

Tullet (2010) published that for the production of best quality day-old chick,

chick yield must be 67% of the fresh egg weight or 67.5% of the setting egg weight

for the eggs that had been stored for short-term period at standard condition. He also

reported that even correct egg weight loss percentage to pipping but too long

incubation result in lower chick yield. He further reported that for every 1% loss in

chick yield is equivalent to about extra three hours in the hatcher.

It is common observation that larger eggs produce larger chicks while smaller

eggs produced smaller chicks. Romanoff (1936) reported that efficiency of

102

incubation can be measured by using the ratio of the weight of the chick at hatching

and the actual weight of the egg at the time of setting. He also concluded that the

optimum ratios correlated with the optimum temperature resulted in the best

hatchability. Abiola et al. (2008) studied that a positive correlation exists between

egg size and chick weight at hatching in broiler chickens. This observation was also

supported by the findings of Abiola (1999) who reported a close correlation between

egg and chick hatching weights in broiler breeder. Pinchasov (1991) further

investigated that magnitude of this correlation between egg weight and chick body

weight declines with the advancement of age of the chick.

Sinclair et al. (1990) studied that chicks hatched from older breeder flocks

are of good quality as they are naturally more resistant to dehydration upon hatching

when compared to smaller chicks hatched from younger breeder flocks. Parkhurst

and Mountney (1988) reported that larger eggs require a longer hatching time. They

observed that in the same flock, large eggs compared to other eggs produced, take

about 12 hours longer time to hatch than smaller ones. This investigation is even true

across the poultry species. Chicken eggs require an incubation period of 21days while

larger eggs from turkeys and peafowl (larger birds) require 28 days incubation period

to hatch. From these studies it can be concluded that incubation conditions should

be adjusted to the size of hatching eggs.

Mbajiorgu (2011) studied the effect of egg size on chick hatch-weight in

indigenous Venda broiler chickens and found that chicks hatched out of medium

sized eggs had significantly higher hatch-weight than that of small and large sized

eggs. He further indicated that chick-hatch weight optimized at hatching egg weight

60 g (r2 = 0.998). His conclusion showed that the egg weight for optimum hatchability

and optimum hatch-weight were different in indigenous Venda chickens.

103

Alsobayel et al. (2013) studied the effect of egg size and age on chick hatch-

weigh percentage (chick yield). A total of 1350 hatching eggs were obtained from

commercial broiler breeders Cobb, Ross 308 and Arbor Acres at 30-35, 40-45 and

50-55 weeks of age, 450 eggs for each breed and 150 eggs for each age. Hatching

eggs for each age were randomly divided into three groups, 50 eggs in each replicate.

Eggs in each group were stored either for 0, 7 or 14 days under 75 to 80% relative

humidity and 14-16 °C. Eggs in each group were individually weighed and

reweighed after storage to determine weight loss. Following usual hatchery practices,

Arbor Acre, Cobb and Ross eggs having average weight, 64.6, 64.7 and 63.7 g were

incubated and hatched chicks were individually weighed and chick weight

percentage of fresh egg weight were calculated. It was observed that hatched chick-

weight percentage of fresh egg weight was significantly (p≤ 0.01) affected by breed,

breeder’s age and storage period. Ross had highest (p≤0.05) chick weight percentage

(chick yield) 69.7% followed by Cobb (69.5%) and Arbor Acre (68.1%). They also

concluded that older broiler breeder flock (50-55 week) had highest (p≤0.05) chick

weight percentage (69.7%) compared to middle aged

40-45 week old (68.7%) and young aged 30-35 week old (68.9%) broiler breeder. It

was also observed that fresh hatching eggs had significantly (p≤0.05) higher chick

weight percent (70.0 %) compared to hatching eggs stored for 14 days (68.3%). This

study was also supported by Abiola (1999) who reported that egg size affects hatched

chick-weight in birds at the time of hatching.

4.2.7 Effect of Egg Size (Weight) and Broiler Breeder Age on Chick Quality of

Broiler

Day-old chick quality is defined according to the judgment of different

people. However, in general, a chick of high performance potential can be defined as

a chick of good quality. This can involve external qualitative aspects or intrinsic

104

factors. Though, day-old chick intrinsic factors cannot be judged visually, its

qualitative aspects can be observed de visu. Also, chick qualitative aspects may be

the only way to select chicks at hatch due to the large numbers of day-old chicks

produced in the hatcheries. Chick quality is important to broiler producers as it is

related to the health state of the chick and future performance. Chicks that are not

healthy and active will not search for food properly and will die or grow less (Fasenko

and O`Dea, 2008). Chick activity and signs of beak, navel and hock abnormalities,

chick weight and chick length are some of the parameters used by commercial

hatcheries to evaluate quality of day old chicks (Tona et al., 2005).

Abiola et al. (2008) reported that small chicks hatched from small eggs while

large chicks hatched from large eggs in Anak broiler breeder. The positive correlation

observed between egg size and chick hatching weight clearly identified the advantage

of initial bigger egg size at the time of setting. In contrast, Sinclair et al. (1990) and

Pinchasov (1991) reported that magnitude of the correlation between egg weight and

chick body weight declines with the increase of age of the broiler chick. Similar

observations were studied by Wyatt et al. (1985) who reported that benefits of

initially higher day-old chick weight attributable to larger-sized egg diminishes

rapidly after hatching while food intake is the main parameter affecting market body

weight of broiler chick.

Tona et al. (2004) reported that chick weight increased with advancing age of

breeders and the data showed that chick weight at 35 and 45 weeks of age in Cobb

broiler breeder was found as 45.27 and 49.44 g, respectively. Alsobayel et al. (2013)

presented a cumulative data of three broiler breeders (Arbor Acres, Cobb and Ross)

which indicated that hatched chick’s attained weight as 41.4, 44.9 and 48.4 g at 30-

35, 40-45 and 50-55 weeks of breeder age. These workers also reported that Cobb

ranked first in chick weight (45.4g) with advancing age of breeders followed by Ross

105

(44.9g) and Arbor Acres (44.5g). In another study, maximum chick weight (51 vs.

40.3g) was accomplished in 59 weeks old Ross-38 breeders as compared to young

breeder at 40 weeks of age (Vieira et al., 2005). Similarly, Ulmer-Franco et al. (2010)

reported that more chick weight (48.9 vs. 37.3g) achieved from 59 weeks old Cobb

breeder flock than that of 29 weeks old flock. Contrary to above studies, Trehan and

Bajwa (2001) did not observe any significant difference in chick weight of 42 and 50

weeks old breeders. Similar results in quail were reported by Yildirim and Yetisir

(1998) who found that the parental age of 22 and 65 weeks had no significant effect

on the chick weight in Japanese quails.

Recent researches have shown that the chick length of day-old chick is now

considered the best method of monitoring visual quality in broiler chicken. Literature

revealed that the large chick length was due to larger egg size. Many other factors

influencing the chick length in broiler chickens are breeder age, blood metabolites

levels, blood hormone levels, blood glucose levels, thyroid and corticosterone

concentration in blood and rates of metabolism (Christensen et al., 1996; Weytjens

et al., 1999; Decuypere and Bruggeman, 2007).

Petek et al. (2010) studied the effects of chick quality indicators such as

feather colour and chick length on the uniformity and growth performances of

broilers. They collected 600 male broiler day-old chicks from a commercial hatchery.

Chicks were distributed on the basis of their feather colour into two groups; deep and

light yellow. The chicks in each group were further distributed according to their

body length into three sub groups as small, middle and large. The chick length of the

smaller subgroup was less than 18.0 cm, middle varied between 18.0-18.3 cm, and

the larger more than 18.3 cm. There was a positive correlation between chick weight

and chick length in all groups at the day of hatch. They observed that larger chicks

showed better growth potential throughout the experiment. The larger chicks

106

exhibited better feeding efficiency and survival rate when compared to smaller

chicks. The feather colour groups showed no-significant (p≥0.05) effects on

subsequent growth parameters. Finally they concluded that the length of day-old

chick was better criteria for selection of good quality day-old chicks as compared to

feather colour.

Molenaar and Reijrink (2011) studied a positive correlation between chick

weight and chick length at day of hatch and at day 7. They collected day-old chicks

hatched from a breeder flock of 33 weeks old. At the hatchery, a total of 60 day-old

chicks were selected for study and were distributed into 3 groups according to chick

length. The chick lengths of larger, middle and smaller groups were 20.0-20.6 cm,

19.2-19.8 cm and 18.2-18.8 cm respectively. All chicks were housed at a broiler farm

having capacity of 9,000 birds and were fed a starter diet. Body weight and organ

weights of all chicks from each group were measured at day 7 of age. Results showed

a positive correlation between chick length at day of hatch and chick weight at day 7

(R=0.68, p<0.001). They further concluded that an extra centimeter of chick length

at day of hatch resulted in on average of 17.8 g extra weight at day 7of age.


4.3.1 Selection of Birds and Experimental Site

The detail is already given in chapter 3, section 3.3.1.

4.3.2 Collection and Storage of Eggs

All the eggs laid during 4-8 hour of light periods, from selected and separated

broiler breeders, were collected from nests at interval of one hour, at the early (30wk),

middle (45wk) and late stage (60wk) of production period. All substandard eggs like

misshapen, cracked, dirty, blood stained, toe punched and elongated were rejected

and only oval shape good quality intact eggs were selected for hatching. The 930

eggs were selected from the hatching eggs at the early, middle and late stage of

107

production period and equally distributed into three egg sized categories (small,

medium and large). A total of 300 hatchable eggs from each egg category (having

310 hatching eggs) were selected and shifted to Rose hatchery, located near

Khannapul Islamabad. These eggs were stored at 20oC and 75% relative humidity for

3 days.

4.3.3 Incubation and Hatching Conditions

At each stage of production period, 300 eggs of each size category (small, medium

and large) were set into 3 trays (replicates). Average egg weight of each replicated

tray having 100 hatchable eggs (experimental eggs) was calculated by an accurate

electronic scale. Additional marked 65 eggs (nonexperimental eggs) were also placed

in each replicated tray for a parallel experiment. These 3 replicated trays of each egg

size category were randomly placed to the top, middle and lower part of the setter of

chick master machine (model ISI, having capacity of 95040 eggs) to assess for

possible environmental difference resulted by position in incubator. The setter was

operated at a temperature of 37.5oC and a relative humidity of 60% during the first

18 day of incubation and eggs were turned after every one hour. On 19 th day of

incubation, eggs of each replicated tray (experimental eggs) were transferred to

separate hatch baskets and placed in a hatcher. The temperature was decreased to

37.0oC and the relative humidity was increased to 70%. After 21 days of incubation

all hatched chicks were taken out of hatchers and shifted to chick’s room of hatchery.

The plan of study is already given in previous chapter as Table 3.2. The following

hatchability parameters were studied during and after incubation period;

4.3.4 Measured Egg Weight Loss during Incubation

At each stage (early, mid and late) of production period, all experimental eggs

of each replicated tray of each egg size category were weighed just prior to setting

into incubator to record average setting weight. At 7, 14 and 18 day of incubation,

all experimental eggs of each replicated tray of each egg size category were removed

108

from incubator and weighed by an electronic scale to calculate their average egg

weight to measure the egg weight loss percentages. After 21 days of incubation

chicks hatched from each replicated tray were counted and taken out of hatcher to

chick’s room. The average chick’s weight of each egg weight category was recorded

to measure chick yield.

4.3.5 Measured Breakout Analysis (Fertility, Hatchability of Set and Fertile

Eggs, Embryonic Mortality, Infertile Eggs, Pipped-not-Hatched Eggs

and Culled Chicks)

At each stage (early, mid and late) of production period, all hatched chicks

from each egg size category were counted to assess hatchability percentage of set

eggs. Chicks that had physical abnormalities (red hocks, weak, or unhealed navels

etc.) were considered as unsalable and culled. The percentage of culled chicks was

calculated on the basis of set eggs. After removing hatched chicks from hatch

basket, all un-hatched eggs were broken open to examine the infertile eggs and

assess the approximate day of embryonic death. The eggs that were pipped but

failed to hatch were isolated and their percentages on the basis of set eggs were

assessed. Embryonic deaths percentages were grouped into 3 categories, early (1st

week of incubation), mid (2nd week of incubation) and late (3rd week of incubation).

The days of embryonic mortalities were assessed on the basis of embryo

development. The eggs showing no embryonic development were considered as

infertile eggs. Infertile egg percentages were calculated on the basis of set eggs.

After calculating the numbers of infertile eggs, hatchability (%) of fertile eggs were

assessed. Hatchability percentages of set and fertile eggs were calculated on the

basis of saleable chicks only.

109

4.3.6 Measured Hatch Percentage

At each stage (early, mid and late) of production period, all hatched out

good quality ‘A’ grade chicks (saleable) from each egg category were counted to

calculate hatch percentage. These ‘A’ grade chicks were then vent sexed to

determine hatch percentage for male and female of broiler sex.

4.3.7 Measured Chick Weight

At each stage of production period, chicks (male and female) hatched out of

all replicates from each egg category (low, medium and heavy weight) were

weighed by an electronic balance to calculate the average chick weight in grams.

4.3.8 Measured Chick Yield

Chick yield can be defined as the average chick weight at the day of hatch

divided by the average egg weight at the time of setting into incubator multiplied by

100. Grade-A chicks in all trays of each treatment (egg weight category) were vent

sexed, counted and weighed by an accurate electronic scale to get average chick

weight for the measurement of chick yield.

4.3.9 Measured Chick Length

At each stage of production period, 30 chicks (15 male and 15 female)

hatched from each egg category (low, medium and heavy weight) were taken at

random. Each selected chick was weighed individually by an accurate electronic

weighing scale (Shimadzu, Model: ATY 224) to assess weight in grams then the

length of the same chick was measured in centimeters from the point of the beak to

the middle toe (nail excluded) by using a calibrated foot. The weight (g) and length

(cm) of individual chicks were recorded. From these readings average chick length

(cm) and chick weight (g) for each egg weight was calculated.


Data were evaluated using Two-way ANOVA and analyzed using GLM

(General Linear Model) procedures of SPSS 16.0 software. When differences were

110

significant, means were compared using Duncan’s Multiple Range tests at the 0.05

level of significance.


4.4.1 Effect of Hatching Egg Size on Egg Weight Loss in Hubbard Classic

Broiler Breeder at Early, Mid and Late Stage of Production Period

Egg weight losses during incubation among different hatching egg size

groups in broiler breeder flock at an early (30 week) stage of production period are

shown in Table 4.1. Significant differences (p≤0.05) were found in egg weight loss

of different egg size groups at early stage of production period. In general, with the

increasing egg weight, egg weight loss percentage was decreased and a significant

difference (p≤0.05) was observed between large and small egg size groups at

different stages of incubation periods. However, non-significant differences (p≥0.05)

were found between small and medium, and medium and large egg size groups at 14

and 18 day of incubation. Cumulative egg weight loss determined during incubation

(before transfer to hatcher) in different egg size groups varied between 11.17 and

11.86% at 30 week of age.


groups in broiler breeder flock at mid (45 week) stage of production period are given

in Table 4.2. Significant differences (p≤0.05) were found in egg weight loss of

different egg size groups at mid stage of production period. However, nonsignificant

difference (p≥0.05) was found between small and medium egg size groups.

Minimum egg weight loss (p≤0.05) was recorded in large egg size group at different

incubation periods. Cumulative egg weight loss determined at the completion of 18

day of incubation in different egg size groups varied between 10.92 and 11.32%.


groups in broiler breeder flock at late (60 week) stage of production period are shown

111

in Table 4.3. A similar trend was found as data collected at early and midstages of

production period. Cumulative egg weight loss determined during incubation in

different egg size groups varied between 10.68 and 11.47% at 60 weeks of age.

The findings of the present study was similar to Aboila et al. (2008), who

reported that although values obtained on weight loss for the 3 egg size categories:

small (41.09-50.97 g), medium (50.98-57.39 g) and large (57.40-69.64 g) in Anak

broilers are comparable with one another, lowest egg weight loss of 11.24% was

obtained for large eggs while highest egg weight loss of 11.57% was recorded for

medium-sized eggs. This was due to the fact that small eggs had larger surface to

volume ratio and that there was an increase in the amount of water removed. Ulmer-

Franco et al. (2010) reported that the percentage of egg weight loss decreased with

the increase in egg size in Cobb 500 broiler breeder hen. Because of the higher

surface to volume ratio in small eggs, they lost the greatest percentage of moisture.

Although, the large eggs had a higher proportion of albumen (greater moisture

contents) than small eggs but lower surface to volume ratio resulted in less egg water

loss. Abanikannda et al. (2011) studied a very low negative and nonsignificant

correlation between egg size and egg weight loss till the 18 th day of incubation that

result in lower weight loss in large-sized eggs when compared to small-sized eggs in

three strains of broilers (Anak- 361, Marshall-359 and Ross282). Similarly, Deeming

(1995) observed the low egg weight loss in the larger ostrich eggs than those from

smaller and medium sized eggs.

Average egg weight loss during incubation (11.22%) regardless the egg size

class in the study is lower than the value of 12.94% reported by Soliman et al.

(1994) for quail eggs. It also is lower than the values of 24.76% reported by

Saylam (1999) and 20.90% reported by Saylam and Sarıca (1999) in quail eggs, and

higher than the values of 1.25% reported by Khan et al. (2013) in Fayoumi eggs

112

which consequently affect the chick weight at hatching. The differences in weight

losses among different studies during incubation can be due to the difference in

species, egg size (weight) and incubation condition provided. Egg weight loss during

incubation of eggs is about utterly due to water diffusion through the shell (Tona et

al., 2001). For the embryonic development during incubation, most of the energy

needed is taken from the fat stocks of the yolk and almost equal mass of metabolic

water is generated by burning of every gram of fat. Egg weight losses during

incubation are functions of egg characteristics (shell thickness, shell membrane

structure, shape index and egg weight) and interacting incubation conditions

(humidity, temperature, turnings and air velocity under

Table 4.1: Effect of egg size on egg weight loss in a hubbard classic broiler breeder

at early (30 week) stage of production period (Means± SE)

Egg size

Egg weight at

time of

incubation (g)

Egg weight loss (%) at different incubation

periods*

7d 14d 18d

Small 51.00a±0.36 4.13a±0.07 8.93a±0.10 11.86a±0.21

Medium 56.07b±0.56 3.92a±0.14 8.56ab±0.14 11.31ab±0.23

Large 61.06c±0.15 3.38b±0.10 8.17b±0.14 11.17b±0.05

SEM 1.464 0.124 0.129 0.140

P-Value 0.000 0.007 0.016 0.081

a-c Means with different letters in a column differ significantly (P≤ 0.05)

*Egg weight loss (%) = [(egg weight at setting − egg weight at different days of

incubation)/egg weight at setting] × 100

113

Table 4.2: Effect of egg size on egg weight loss in hubbard classic broiler breeder

at mid (45 week) stage of production period (Means± SE)

Egg size

Egg weight at

time of

incubation(g)


periods*

7d 14d 18d

Small 60.05a±0.04 3.97a±0.14 8.86a±0.10 11.32a±0.08

Medium 65.03b±0.04 3.77a±0.15 8.66a±0.07 11.22a±0.17

Large 70.03c±0.04 3.27b±0.17 8.16b±0.06 10.92b±0.08

SEM 1.4406 0.0811 0.404 0.0648

P-Value 0.000 0.034 0.046 0.035




114

Table 4.3: Effect of egg size on egg weight loss in hubbard classic broiler breeder

at late (60 week) stage of production period (Means± SE)

Egg size

Egg weight at

time of

incubation (g)


periods*

7d 14d 18d

Small 63.09a±0.21 3.57a±0.03 8.89a±0.07 11.47a±0.22

Medium 68.85b±0.23 3.56ab±0.06 8.62b±0.05 11.09ab±0.03

Large 74.81c±0.11 3.40b±0.05 8.30c±0.09 10.68b±0.06

SEM 1.69 0.0358 0.09249 0.13174

P-Value 0.000 0.075 0.003 0.016




115

which the eggs were set (Gonzalez et al., 1999). Deeming (1995) determined that 10-

12% weight loss is necessary during incubation in order to get a good incubation

result in stored and non-stored eggs. Similarly Tona et al. (2001) reported that

maximum numbers of day-old chicks hatched out from fertile eggs when cumulative

water loss during 18 days of incubation varied between 10.9 and 11.1%.

It is concluded that minimum egg weight loss occurred in large-sized egg

groups at all stages of production period and at different incubation periods.

4.4.2 Effect of Broiler Breeder Age on Egg Weight Loss during Incubation

Egg weight loss during incubation among different age groups of broiler

breeder flock are shown in Table 4.4. Egg weight loss percent was significantly

(p≤0.05) affected by breeder’s age. Data showed that egg weight losses decreased

with advancing the age of breeder hens. The results of this study are in line with the

findings of Reis et al. (1997), who reported that egg weight loss percentage in the

eggs obtained from older broiler breeders was lower than that of eggs from younger

breeders. This can be explained by the facts of larger egg weight and less shell area

per unit of interior egg contents in the older breeders when compared to younger

breeders. Alsobayel et al. (2013) reported that cumulative values of egg weight losses

in three breeds (Ross, Arbor acres and Cobb) were found as 1.19%, 1.11% and 1.08%

at 30-35, 40-45 and 50-55 weeks of age, respectively. Results showed that Ross had

significantly (p≤ 0.05) the highest (1.3%) and the lowest (1.0%) egg weight loss

percent at 30-35 and 40-45 weeks of age, respectively, while Arbor Acres had

significantly (p≤0.05) the lowest (1.80%) egg weight loss at 30-35 weeks of age.

Arbor acres showed the highest egg weight loss with advancing age

116

4.4: Effect of age on egg weight loss in broiler breeder (Means± SE)

Age

(Weeks)

Egg weight at

time of

incubation (g)


periods*

7d 14d 18d

30 56.05a±1.46 3.89a±0.12 8.84a±0.04 11.45a±0.14

45 65.03b±1.44 3.81a±0.08 8.54b±0.09 11.22ab±0.06

60 68.92b±1.69 3.51b±0.04 8.56b±0.13 11.08b±0.13

SEM 1.35824 0.05815 0.05815 0.07145

P-Value 0.000 0.015 0.085 0.100

a-c Means with different letters in a column differ significantly (P≤ 0.05) *Egg

Weight Loss (%) = [(egg weight at setting − egg weight at different days of


117

whereas Ross had the highest and the lowest egg weight loss at early and middle age,

respectively. This might be due to the fact that shell quality deterioration is higher

with advancing age for Arbor Acres compared to other breeds. Zakaria et al. (2009)

provided the evidence that egg weight loss by the evaporation of water was the result

of deterioration of the albumen quality and evaporation of water through the eggshell

that were influenced by variation in the albumen quality due to flock age, egg storage

conditions and duration (Tona et al., 2001). In the current study, the values of egg

weight loss in Hubbard strain at different ages were higher than the above study.

In another study, Abanikannda et al. (2011) reported that the egg weight loss

in Anak broiler breed was 17.62% and 6.92% higher than that of Ross and Marshall

breed, respectively. Data showed that Anak breed exhibited the greatest weight loss

which had the smallest egg size when compared to the other two broiler breeder

breeds during the first 18 days of incubation. The results on the mean percentage loss

in the present study (11.25% at 18 d of incubation) are close to a loss of 11.40% as

reported by Reis et al. (1997). Abudabos (2010) reported that egg weight loss from

Ross strain-32 was 3.4, 4.6 and 4.9% at 7, 14 and 19 d of incubation, respectively.

Similarly, egg weight loss in Ross strain-36 was 3.5, 4.7 and 4.7% at 7, 14 and 19 d

of incubation, respectively. The egg weight loss from Cobb strain-26 was reported

as 2.9, 4.1 and 3.8% at 7, 14 and 19 d of incubation, respectively and Cobb strain-44

was found as 2.7, 4.2 and 4.0% at 7, 14 and 19 d of incubation, respectively. In the

present study, the overall values of egg weight losses in Hubbard breed at different

incubation periods were higher than the above study.

It is concluded that egg weight losses were decreased with advancing the age

of broiler breeder hens.

118

4.4.3 Effect of Hatching Egg Size on Hatchability Traits in Hubbard Classic

Broiler Breeder at Early, Mid and Late Stage of Production Period

The influence of egg size on fertility and hatchability traits (hatchability,

embryonic mortality, infertile eggs, pipped-not-hatched eggs and culled chicks) in

broiler breeder flock at an early (30 week) stage of production period are revealed in

Table 4.5. At this stage of production period, an average egg weight of small, medium

and large eggs was 51.00, 56.07 and 61.06 g, respectively. Egg size had significant

(p≤0.05) effect on fertility and hatchability parameters except pippednot-hatched

eggs and culled chicks at early stage of production period. Generally, it was observed

that fertility and hatchability percentage increased with increasing the egg size.

Maximum fertility (p≤0.05) was recorded in large-sized egg group (95.67%),

followed by medium (92.67%) and small (90.33%) sized egg groups.

Similarly, better hatchability percentage (out of set eggs or fertile eggs) was

found (p≤0.05) in large-sized egg group (86.67 or 90.59%, respectively), followed

by medium (82.33 or 88.81%, respectively) and small (70.67 or 78.11%,

respectively) sized egg groups. However, there non-significant difference (p≥0.05)

was found between medium and small-sized egg groups. Maximum embryonic

mortality (p≤0.05) during incubation was recorded in small-sized egg group,

followed by medium and large-sized egg groups. At early stage of production period,

maximum embryonic mortality (4.70%) was found in small-sized egg group during

1st week of incubation. Higher percentage of infertile eggs (p≤0.05) was also found

in small sized-egg group (9.67%), followed by medium (7.33%) and large (4.33%)

sized-egg groups. No significant (p≥0.05) effect of egg size was observed on pipped-

not-hatched eggs and culled day-old chicks.

The effect of egg size on fertility and hatchability traits (hatchability,


broiler breeder flock at mid (45 week) stage of production period are shown in Table

119

4.6. At this stage of production, an average egg weight of small, medium and large

eggs was 60.05, 65.03 and 70.03 g, respectively. Egg size had significant

(p≤0.05) effect on fertility and hatchability traits except pipped-not-hatched eggs at

mid stage of production period. Maximum fertility (p≤0.05) was noticed in small egg

size group (96.65%), followed by medium (93.33%) and large (90.13%) egg size

groups. Similarly, maximum hatchability percentage (out of set eggs or fertile eggs)

was achieved (p≤0.05) in small egg size group (89.67 or 92.74%, respectively),

followed by medium (83.63 or 89.61%, respectively) and large

(78.33 or 86.72%, respectively) egg size groups. Maximum embryonic mortality

(p≤0.05) during incubation was recorded in large size egg group, followed by

medium and small egg size groups. At mid stage of production period, maximum

embryonic mortality (3.3%) was found in large size egg group during 1st week of

incubation. Higher percentage of infertile eggs (p≤0.05) was also found in large egg

size group (9.67%), followed by medium (6.67%) and small (3.33%) size egg groups.

No significant (p≥0.05) effect of egg size was observed on pipped-nothatched eggs.

Maximum chicks (p≤.05) were culled in large size egg group (2.0%).

The influence of egg size on fertility and hatchability traits (hatchability,


broiler breeder flock at late (60 week) stage of production period are given in Table

4.7. At late stage of production period, an average egg weight of small, medium and

large eggs was 63.09, 68.85 and 74.81 g, respectively. Egg size had significant

(p≤0.05) effect on fertility and hatchability parameters at 60 weeks of age. Maximum

fertility (p≤0.05) was found in small egg size group (91.0%), followed by medium

(89.33%) and large (85.67%) egg size groups. Similarly, better hatchability

percentage (out of set eggs or fertile eggs) was recorded (p≤0.05) in small egg size

group (82.00 or 90.11%, respectively), followed by medium (75.00 or 83.95%,

respectively) and large (64.33 or 75.08%, respectively) egg size groups.

120

Maximum embryonic mortality (p≤0.05) during incubation was seen in large size

egg group, followed by medium and small egg size groups. At late stage of

production period, maximum embryonic mortality (5.67%) was observed in large

size egg group during 1st week of incubation. Higher percentage of infertile eggs

(p≤0.05) was also found in large egg size group (14.33%), followed by medium

(11%) and small (9.0%) size egg groups. More pipped-not-hatched eggs (p≤0.05)

were observed in large size egg group (4.33%). In similar pattern, maximum chicks

(p≤0.05) were also culled in large size egg group (3.67%).

The best combination of fertility and hatchability values were observed in the

small and medium size eggs at mid and late stage of production period while lowest

combination of fertility and hatchability value was recorded in large size eggs (74.81

g) at late stage of production cycle.

Unquestionably, hatchability and fertility are two major traits that highly

influence on the quantity of day-old chicks. It is therefore very important to

understand the effect of egg size on fertility and hatchability traits. There is a scarcity

of information on the effect of egg size on hatchability in Hubbard broiler chickens.

The results of current study are agreed to other studies. Kirk et al. (1980) studied that

fertility and hatchability of eggs weighing more than 70 grams in the post-peak

broiler breeders (60 week) declined by 11 and 9% respectively. This effect was

explained by a relationship between egg weight and breeder age, as best hatchability

for younger broiler breeders was observed at an average weight of 60 gram. DeWitt

and Schwalbach (2004) reported that large size eggs recorded to have higher

hatchability in New Hampshire and Red Rhode Island chicken breeds at 30 weeks of

age. In previous study, Wilson (1991) also reported that large sizedeggs (ranging

from 60 to 67 g) had a higher hatchability values than that of medium and small-

sized eggs. He suggested that egg-size (60 to 69 g) group was best suited for

121

incubation. Similarly, Mbajiorgu (2011) reported that maximum hatchability in

broiler breeders can be achieved at an average egg weight of 67 gram. Similar results

were obtained in the current study, best fertility and hatchability traits were obtained

in small and medium egg size groups having 60 to 68.85g egg weight at the age of

45 to 60 weeks old and large egg size group having such desired egg weight at 30

weeks of age. These results further supported by Ulmer-Franco et al. (2010), who

studied the effect of egg size on the hatchability of a 43 week old Cobb 500 flock and

observed low hatchability for the larger eggs than the average eggs. This low

hatchability in larger eggs was the result of both higher late embryonic deaths and

increased number of culled chicks. They also observed that there were lowest

numbers of culled day-old chicks in the smaller and medium eggs at 43 weeks of age.

Wilson (1991) also recommended that

hatchability is a distinctive fitness trait with low heritability which showed that Table

4.5: Effect of egg size on fertility and hatchability parameters in hubbard

classic broiler breeder at early (30 week) stage of production period

(Means± SE)

Parameters

Egg size

SEM P-


Av. egg

weight (g) 51.00c±0.36 56.07b±0.56 61.06a± 0.15 1.46 0.00

Fertility (%)* 90.33b±2.33 92.67ab±0.88 95.67a±0.33 1.06 0.104

Hatchability

of set eggs

(%) **

70.67b±0.93 82.33ab±2.73 86.67a±1.76 2.80 0.021

Hatchability

of fertile eggs

(%)***

78.11b±2.43 88.81b±2.12 90.59a±1.80 2.22 0.012

Embryonic

mortality (%)

1stwk 4.70a±1.15 3.0b±0.58 3.0b±0.58 0.64 0.064

2ndwk 4.33a±0.67 1.67b±0.67 1.00b±0.00 0.58 0.011

3rdwk 4.67a±1.20 2.01b±0.33 1.60c±1.00 0.61 0.185

Infertile eggs

(%) 9.67a±2.33 7.33ab±0.89 4.33b±0.33 1.06 0.104

122

Piped-

nothatched

eggs (%)

3.00±0.58 1.67±0.33 1.67±0.33 0.31 0.113

Culled chicks

(%)**** 2.33±0.33 1.33±0.33 1.33±0.33 0.24 0.125

a-cMeans with different letters in rows differ significantly (P≤ 0.05)

*(Number of fertile eggs/number of eggs set) × 100

** (Number of salable chicks hatched/number of total eggs set) × 100

*** (Number of salable chicks hatched/number of fertile eggs set) × 100

**** (Number of non-salable chicks culled at hatching/total number of

eggs set) × 100

Table 4.6: Effect of egg size on fertility and hatchability parameters in hubbard

classic broiler breeder at mid (45 week) stage of production period

(Means± SE)

Parameters

Egg size

SEM P-


Av. egg weight

(g) 60.05c±0.04 65.03b±0.04 70.03a±0.04 1.4406 0.000

Fertility (%)* 96.67a±0.89 93.33b±0.33 90.33c±0.33 0.9590 0.001

Hatchability of

set eggs (%) ** 89.67a±1.76 83.67b±0.33 78.33c±0.33 1.7195 0.001

Hatchability of

fertile eggs

(%)***

92.74a±1.08 89.64b±0.34 86.72c±0.60 0.9446 0.004

Embryonic

mortality (%)

1stwk 2.0b±0.0 2.8a±0.3 3.3a±0.0 0.2222 0.007

2ndwk 1.33b±0.3 2.0ab±0.0 2.33a±0.3 0.2003 0.098

3rdwk 1.67b±0.3 2.33ab±0.3 3.00a±0.0 1.789 0.037

Infertile eggs

(%) 3.33c±0.89 6.67b±0.33 9.67a±0.33 0.9590 0.001

123

Piped-

nothatched eggs

(%)

1.33±0.33 1.00±0.00 1.67±0.33 0.1666 0.296

Culled

chicks(%)**** 0.67b±0.33 1.00a±0.00 2.00a±0.00 0.222 0.007




*** (Number of salable chicks hatched/number of fertile eggs set) × 100 ****

(Number of non-salable chicks culled at hatching/total number of eggs set) ×

100

Table 4.7: Effect of egg size on fertility and hatchability parameters in

hubbard classic broiler breeder at late (60 week) stage of production

period (Means± SE)

Parameters Egg size

SEM P-


Av. egg weight

(g) 63.09c±0.21 68.85b±0.23 74.81a±0.11 1.69 0.00

Fertility (%)* 91.0a±0.00 89.33b±0.33 85.67c±0.67 0.82 0.000

Hatchability of

set eggs (%) ** 82.00a±0.58 75.00b±0.58 64.33c±1.45 2.61 0.000

Hatchability of

fertile eggs

(%)***

90.11a±0.63 83.95b±0.41 75.08c±1.18 2.22 0.000

Embryonic

mortality (%)

1stwk 1.33a±0.3 3.33b±0.3 5.67c±0.3 0.648 0.000

2ndwk 1.67a±0.3 2.33ab±0.3 3.0b±0.3 0.235 0.037

3rdwk 2.33a±0.3 4.00b±0.0 4.67b±0.3 0.372 0.002

Infertile eggs

(%) 9.00a±0.0 11.00b±0.0 14.33c±0.67 0.801 0.000

Piped-

nothatched eggs

(%)

2.00a±0.0 2.00a±0.00 4.33b±0.33 0.4006 0.000

124

Culled

chicks(%)**** 1.67a±0.33 2.33a±0.3 3.67b±0.3 0.3379 0.014

a-cMeans with different letters in a rows differ significantly (P≤ 0.05)



*** (Number of salable chicks hatched/number of fertile eggs set) × 100 ****

(Number of non-salable chicks culled at hatching/total number of eggs set) ×

100

improvement in hatchability by selection take a long time and hence improvement in

breeder farm and hatchery management and optimization of hatching egg weight are

therefore the most promising route for improvement.

Literature showed inconsistent results due to certain factors like breed and

age of flock. Nowaczewski et al. (2010) reported that the hatchability for large size

group from fertilized and set eggs was significantly higher 6.8 and 9.3% respectively

in comparison with small size egg group (≤10.50 g) of Japanese quail. They further

observed that there were non-significant difference in the case of fertilized eggs, the

proportion of necrosed embryos and un-hatched chicks between the large and small

sized egg groups. Ng’ambi et al. (2013) determined the effect of egg size (<49 g, 50-

59 g, 60-69 g and >70 g) on hatchability in indigenous Venda chickens. They reported

that egg weight was positively and strongly correlated with egg hatchability.

Maximum hatchability was found in large size eggs (73.9%). Dudusola (2013)

reported that higher fertility was observed in the heavy egg weight category of 36

weeks old quail (92.59%) compared to that of the light weight category (89.90%).

Madeddu et al. (2013) reported that egg size of Italian bantam breed (Mericaneldella

Brianza) significantly affect the fertility and hatchability and small egg size was

associated with greater embryonic deaths (66%) compared to large egg size (38% to

50%). Small sized eggs were associated with greater embryonic deaths, resulting in

125

a low hatchability in the Cobb strain (Pedroso et al., 2005) as in case of the present

study, more embryonic deaths occurred in small egg size (51 g) at 30 weeks of age.

In small eggs there may be insufficient nutrients for the embryonic development and

metabolism and low energy for the hatching out process that result in low hatchability

(Mcloughlin and Gous, 1999).

In contrast of above studies, Abiola et al. (2008) reported that medium sized eggs of

Anak broiler (average 50 g) might be suitable for setting in order to obtain good

hatchability, best result of weight gain and lower mortality. However, these workers

recommended that where carcass traits are of special consideration, the large eggs

would be preferred for setting. Similarly, Alabi et al. (2012) reported that medium

egg size of Potchefstroom Koekoek chicks had the highest (p≤0.05) hatchability

(77%) than large (64%) and small (55%) egg size category. Further they reported that

smaller eggs had higher (p≤0.05) embryonic deaths (45%) when compared to larger

eggs (36%) and medium eggs (31%). Similarly, Rashid et al. (2013) also reported

that medium sized eggs had higher (p≤0.05) hatchability than those of large sized

eggs in Desi, Fayoumi, and crossbred (Rhode Island Red X Fayoumi) chickens.

These workers also suggested that if performance and carcass traits are of high

importance then large eggs can be considered. The reason for the differences in

hatchability among egg size groups in all above studies might be due to breed

differences. The results of the above studies were also similar to the current study

which revealed that better fertility and hatching traits were attained in medium sized

eggs (60-65 g) at the age of 45 weeks.

Abudabos (2010) determined the effect of broiler breeder strain (Ross 308;

Cobb 500) and parent flock age (Ross at 32 and 36 weeks; Cobb at 26 and 44 weeks

of age) on hatchability, fertile hatchability, and egg break out analysis were

examined. He reported that maximum hatchability (out of set eggs and fertile eggs)

was recorded in Ross-32 (87.3 and 90.3%, respectively), followed by Cobb-26 (85.2

126

and 92.3%, respectively), Ross-36 (80.8 and 85.9%, respectively) and Cobb44 (70.4

and 82.8%, respectively). In the current study, hatchability (out of set an fertile eggs)

of broiler breeder at age of 30 week was 79.89 and 85.84%, respectively, which was

very close to Ross-36 in the above study. In the same study, he reported that embryo

mortality in Cobb-26 was found as 1.8, 0.7 and 2.2% during 1-7 d, 8-14 d and 15-21

d of incubation, respectively and Cobb-44 was recorded as 1.8, 8.5 and 2.2% during

1-7 d, 8-14 d and 15-21 d of incubation, respectively. Similarly, embryo mortality in

Ross-32 was found as 2.6, 1.1 and 1.1% during 1-7 d, 8-14 d and 15-21 d of

incubation, respectively and Ross-36 was found as 2.5, 3.0 and 1.1% during 1-7 d,

8-14 d and 15-21 d of incubation, respectively. These results showed non-significant

differences in both early and late death of the embryo due to strain or age. However,

mid embryonic death was detected and it was associated with eggs from older hens

(p≤0.01) compared to the other treatments. In the present study, overall embryonic

mortality values were higher in Hubbard broiler than other strains as mentioned in

the above study. However, in the present study, more embryos death during mid to

late incubation (2.33 to 3.67%) was occurred in older hen flock (45 to 60 week of

age). In younger flock (30 week of age), maximum embryonic death occurred in

early incubation period (3.30%).

Butcher and Nilipour (2012) provided practical industry standards of different

parameters in an egg breakout analysis. They advised that these standards could be

used as a guide for comparison purposes. They compiled data from breakout analyses

conducted during a five year period from the broiler breeder flocks in

Panama. These data were designed for the 40 weeks of production cycle in broiler

breeders. The data showed that percentages of hatch, dead chicks, pipped-nothatched

eggs and infertile eggs should be 85, 0.25, 1.25 and 4.50, respectively. Contrary to

above standards, present experiment (which was conducted in field condition)

showed an average percentage of hatch, dead chicks, pipped-not-hatched eggs and

127

infertile eggs at the age of 45 weeks old regardless the egg size were 83.89, 1.67,

1.33 and 6.55%, respectively. When these results were compared with standards,

parameters of hatchability, dead chicks (non-saleable culled chicks) and pipped-not-

hatched eggs were satisfied whereas, values of infertile eggs were high than above

standards that might be difference in breeder age.

At particular flock age, poor chick quality has been associated with larger

than average egg weight in broiler breeders (Lawrence et al., 2004; Kumpula and

Fasenko, 2004). These findings are harmony with the results of present study in

which maximum culled chicks were recorded in large size eggs than medium and

small egg size groups at mid (2.00, 0.67 and 1.00, respectively) and late (3.66, 2.33

and 1.67, respectively) production stage periods.

It is concluded that for attaining better fertility and hatchability traits in broiler

breeder flocks, regardless the age, medium egg weight (60-65g) should be selected

for incubation.

4.4.4 Effect of Broiler Breeder Age on Fertility and Hatchability Traits

The effect of broiler breeder age on fertility and hatchability traits

(hatchability, embryonic mortality, infertile eggs, pipped-not-hatched eggs and

culled chicks) are given in Table 4.8. Age of the hens had a significant (p≤0.05) effect

on fertility and hatchability traits except embryonic mortality. Low fertility and

hatchability (out of set eggs and fertile eggs) were recorded (p≤0.05) in older hens at

the age of 60 weeks, however, non-significant difference (p≥0.05) was observed

between these parameters at 30 and 45 weeks of age. Age of hen was not influenced

(p≥0.05) on embryonic mortality during incubation. Numerically, more embryonic

deaths occurred in flocks at older age. Infertile eggs, culled chicks and pipped-not-

hatched eggs percentages were higher in older flock (60 week) when compared with

younger flocks (30 and 45 weeks) in Hubbard classic broiler

128

breeder strain.

The results of the present study were concurred with the findings of Tona et

al. (2001), who conducted a continuous study on a Cobb broiler breeder flock (from

27 to 60 week of age), and observed the lowest total embryonic deaths and highest

hatchability at 40 week of age. The poorest hatchability and highest embryonic

deaths were observed at the end of the study period (60 week of breeder age). The

workers hypothesized that these findings might be the result of a combined effect of

lower than optimal ventilation and high embryonic heat production in the setter

because of higher egg weight at 60 week of age. Vieira et al. (2005) found that eggs

from old Ross-38 breeders (59 weeks old) were known to have an overall reduction

in hatchability (73.5%) when compared to those from young breeder (88.3% and

82.3% for 27 and 40 weeks old, respectively), which is mostly related with increased

embryonic mortality and reduction in fertility. Similar results were obtained in the

present study in which fertility and hatchability reduced and increased embryonic

mortality (p≥0.05) with advancing the age of Hubbard Classic strain. El-Safty (2012)

reported that eggs laid by old broiler breeders revealed higher infertility and total

embryonic deaths, resulting in lower hatching percentage, especially after 45 weeks

of age. In concord with this result, Abudabos (2010) reported that hen’s age affected

hatchability and there was reduction of hatchability with advance age. This effect

was more pronounced in the Cobb strain because of the bigger range of age (18 weeks

difference) compared to 4 weeks for Ross strain.

In previous works (Kirk et al., 1980), it was observed that fertility and

hatchability decreased with age, fertility and hatchability of 60 weeks broiler

breeders were declined by 11% and 9% respectively, as in case of the present study,

10.24% fertility and 7.41% hatchability declined at 60 weeks of broiler breeder

Hubbard Classic strain. From a biological point of view, the fertility of eggs is

affected by hen such as her ability to store sperm, to ovulate the egg cell and to

129

provide an optimum environment for the formation and growth of the embryo

(Brillard, 2003). The hatchability of all settable eggs is a function of the significant

effect of both paternal and maternal components (parents) on fertility and early

embryo survival and incubation conditions. Literature showed that hatchability

reduction in the eggs of old broiler breeders is a result of many factors, including

increased egg size (Leeson and Summers, 2000), higher early and late embryonic

deaths (Elibol and Brake, 2003), poorer shell quality due to bigger surface area

(Bennett, 1992), albumen quality deterioration (Tona et al., 2004) and increased of

the yolk cholesterol contents (Dikmen and Sahan, 2007).

Ransin (2005) provided the fertility and hatchability goals at certain ages of

breeder flock. The standard showed that fertility and hatchability of 28, 32, 45 and

60 weeks old breeder flock should be 91 and 83%, 97 and 88%, 97 and 88% and 97

and 88%, respectively. In contrast to above standard, the current study showed that

fertility and hatchability of 30, 45 and 60 weeks old breeder flock were found as

Table 4.8: Effect of broiler breeder age on fertility and hatchability traits

(Means± SE)

Parameters Age (Weeks)

SEM P-

Value 30 45 60

Fertility (%)* 92.89a±1.06 93.44a±0.96 83.87b±0.82 0.673 0.003

Hatchability of

set eggs (%) ** 79.89ab±2.80 83.89a±1.72 73.74b±2.61 1.573 0.023

Hatchability of

fertile eggs

(%)***

85.84ab±2.22 89.70a±0.944 83.05b±2.22 1.178 0.063

Embryonic

mortality (%)

1stwk 3.30±0.6 2.78±0.2 3.44±0.6 0.316 0.299

2ndwk 2.33±0.6 1.89±0.2 2.33±0.2 0.213 0.636

130

3rdwk 3.11±0.6 2.33±0.2 3.67±0.37 0.264 0.115

Infertile eggs

(%) 7.11b±1.0 6.55b±0.9 11.44a±0.8 0.677 0.002

Piped-

nothatched eggs

(%)

1.80b±0.3 1.33b±0.2 2.78a±0.4 0.206 0.011

Culled

chicks(%)**** 1.22b±0.22 1.67b±0.23 2.56a±0.33 0.185 0.006

a-c Means with different letters in a rows differ significantly (P≤ 0.05)



*** (Number of salable chicks hatched/number of fertile eggs set) × 100

**** (Number of non-salable chicks culled at hatching/total number of

eggs set) × 100

92.89 and 85.84%, 93.44 and 89.70% and 83.87 and 83.05%, respectively. The

values of fertility were comparatively low than standard due to which hatchability

percentages were also low except 45 weeks old breeder flock.

The percentage of low quality chicks was reported to be higher for older (45-

week) than younger (35-week) flocks (Tona et al., 2004). Similar results are observed

in the present study in which more culled chicks were recorded in older flock (2.56%)

as compared to younger (1.22%) flocks.

It is concluded that fertility and hatchability of the flock were reduced with

advancing the age of breeder hen. However, embryonic mortality, infertile eggs,

pipped-not-hatched eggs and culled chicks (not-saleable chicks) were increased with

advancing the age of breeder hen. Furthermore, maximum fertility and hatchability

values were observed at 45 week of age.

131

4.4.5 Influence of Egg Size on Chick Quality in Hubbard Broiler Breeder at

Early, Mid and Late Stage of Production Period

The influence of egg size on chick weight, chick yield and chick length in

commercial Hubbard Classic broiler breeder flock at an early (30 weeks) stage of

production period is shown in Table 4.9. Hatching egg size had a significant (p≤0.05)

effect on chick weight (male and female chick). It was observed that chick weight

and chick length were augmented (p≤0.05) with increasing the egg size in both male

and female broiler chicks. However, egg size was not influenced

(p≥0.05) on chick yield (male and female chick).


commercial Hubbard Classic broiler breeder flock at mid (45 week) stage of

production period is given in Table 4.10. Egg size had a significant (p≤0.05) effect

on chick weight and chick length (male and female chick). Data revealed that chick

weight and chick length were amplified (p≤0.05) with increasing the egg size.

However, egg size was not influenced (p≥0.05) on chick yield (male and female

chick) in both male and female broiler chicks.


commercial Hubbard Classic broiler breeder flock at late (60 week) stage of

production period is presented in Table 4.11. Egg size had a significant (p≤0.05)

effect on chick weight, chick yield and chick length (male and female chick). Data

revealed that chick weight, chick yield and chick length were improved (p≤0.05) with

increasing the egg size in both male and female broiler chicks.

There is a paucity of information of the effect of egg size on chick weight in

Hubbard broiler chickens. Chick weight is the most widely used indicator for day-

old chick quality assessment (Decuypere et al., 2002). It is known that a positive

correlation exists between chick weight and egg weight in broiler chickens (Abiola

132

et al., 2008). Vieira et al. (2005) found that more chick weight (53.4g vs. 41g)

obtained from large egg size (72.7± 2.5g) as compared to small egg size (57.7± 1.8

g) in 40 weeks old Ross-38 breeders. Similar trend was observed in the current

experiment, chicks gained more weight (47.50 vs. 40.0g) from large egg size (70 g)

than that of small egg size (60g) at mid (45 weeks) stage of production in Hubbard

breeder. Ulmer-Franco et al. (2010) reported that more chick weight (46.5g) achieved

from large egg size as compared to medium egg size (43g) and small egg size (39.9g)

in commercial Cobb broiler breeder. In the current experiment, the values of chick

weight in Hubbard broiler breeder were found higher than those Table 4.9: Effect of

egg size on chick quality in hubbard classic broiler breeder at early (30

week) stage of production period (Means± SE)

Parameters

Egg size

SEM P-


Eggs set (No.) 100 100 100 - -

Egg weight (g) 51.00c±0.36 56.07b±0.56 61.06a±0.15 1.464 0.000

Chick weight

(g)

Male 36.76c±0.22

39.64b±0.22 43.80a±0.41 0.302 0.000

Female 36.02c±0.26

38.58b±0.27 42.87a±0.38 0.296 0.000

Chick yield*

(%)

Male 69.91±0.40 69.96±0.11 70.66±0.86 0.302 0.265

Female 68.58±0.17 68.67±0.03 70.34±1.32 0.478 0.590

Chick length

(cm)

Male 17.72c±0.06

18.14b±0.05 18.34a±0.05 0.040 0.000

Female 17.82b±0.06

17.90b±0.06 18.17a±0.07

0.038 0.002


133

*(chick weight/set egg weight) ×100

Table 4.10: Effect of egg size on chick quality in hubbard classic broiler breeder


Parameters Egg size

SEM P-


Eggs set (No.) 100 100 100 - -

Egg weight (g) 60.05c±0.04

65.03b±0.04 70.03a±0.04 1.440 0.000

Chick weight

(g)

Male 41.90c±0.02 45.46b±0.11 49.03a±0.25 1.029 0.000

Female 41.68c±0.11 45.13b±0.03 48.73a ±0.04 1.017 0.000

Chick

yield*(%)

Male 69.79±0.06 69.90±0.22 70.02±0.06 0.156 0.206

Female 69.42±0.37 69.40±0.14 69.59±0.23 0.221 0.578

Chick length

(cm)

Male 18.99c±0.05

19.60b±0.05 19.72a±0.04 0.0395 0.000

Female 18.98c±0.07

19.37b±0.06 19.55a±0.06 0.0405 0.000



134

Table 4.1 1: Effect of egg size on chick quality in hubbard classic broiler breeder


Parameters

Egg size

SEM P-


Eggs set (No.) 100 100 100 - -

Egg weight

(g)

63.09c±0.21 68.85b±0.23 74.81a±0.11 1.690 0.000

Chick weight

(g)

Male 43.33c±0.15

48.40b±0.16 52.36a±0.16 0.331 0.000

Female 43.29c±0.15

48.24b±0.15 52.38a±0.16 0.333 0.000

Chick

yield*(%)

Male 69.97b±0.14

70.22ab±0.02 70.38a±0.06 0.075 0.049

Female 69.84b±0.12

70.12a±0.03 70.17a±0.03 0.064 0.042

Chick length

(cm)

Male 19.89c±0.05

20.34b±0.04 20.74a±0.04 0.0390 0.000

Female 19.95c±0.06 20.41b±0.05

20.69a±0.05 0.0392 0.000



obtained in above Cobb breeder study at any age or egg size groups.

135

Abiola et al. (2008) reported that small chicks hatched from small eggs while

large chicks hatched from large eggs in Anak broiler breeder. This positive

correlation observed between egg size and chick hatching weight clearly identified

the advantage of initial bigger egg size at the time of setting. In contrast, Sinclair et

al. (1990) and Pinchasov (1991) reported that the magnitude of correlation between

egg weight and chick body weight decreased with the age of the broiler chick and the

benefits of initially higher day-old chick weight diminishes rapidly after hatching.

Wyatt et al. (1985) reported that feed intake is the main factor affecting final market

body weight of broiler chicken. The results of final live weight also confirmed the

significance of initial bigger egg size for incubation. Recently,

Rashid et al. (2013) reported that chick weight from large eggs (>45g) were

(p≤0.05) higher than those of small eggs (<41g) in three rural breeds (crossbred

(Rhode Island Red X Fayoumi), Fayoumi and Desi. Williams (1994) suggested that

heavier eggs contained more nutrients than small eggs and hence, developing

embryos from heavier eggs tended to have more nutrients for their growth

requirements.

Similar results were obtained in other poultry species, Ng’ambi et al. (2013)

reported that chick weight improved with increasing the egg size in indigenous Venda

chickens. The data showed that the hatched chicks had 29, 31, 32 and 33g weight for

different egg size <49g, 50-59g, 60-69g and >70g, respectively. Similarly in another

study, the chick weight of Japanese quail (Cortunix cortunix japonica) was increased

significantly as a result of the increasing egg size

(Dudusola, 2013). This increase in chick size due to increasing egg weight is

attributable to the fact that egg weight, yolk weight and albumen weight improved as

the age increased in chickens while egg shell quality deteriorated (Hurnik et al.,

1997).

136

More recent research showed that the chick length should be considered the

best method to evaluate the visual quality of broiler day-old chick (Mukhtar et al.,

2013). Literature revealed that the large chick length was due to heavier egg weight

(Decuypere and Bruggeman, 2007), as in case of present study. The other factors that

had effects on chick length are breeder age, blood glucose and metabolites levels

(Decuypere and Bruggeman, 2007), concentration of thyroxin and Corticosterone

hormone in blood (Christensen et al., 1996), thermoregulatory ability and rates of

metabolism of parent flock (Weytjens et al., 1999).

Alsobayel et al. (2013) presented a cumulative data of three broiler breeders

which indicated that hatching eggs having 59.3, 64.6, 64.8 and 68.9 g weights yielded

chick percentage (chick yield) as 68.9, 68.1, 68.7 and 69.7% respectively. Similarly,

in current study hatching eggs having 56.7, 63.09, 65.04 and 68.85 g weights yielded

chick percentage (chick yield) as 69.31, 69.90, 69.65 and 70.17% respectively. The

current chick yield percentages are somewhat higher as compared to above study;

this may be due to breed (strain) difference as Alsobayel et al. (2013) also showed

that Ross had higher chick yield (69.7%) compared to Cobb (69.5%) and Arbor Acre

(68.1%) strain.

It is concluded that maximum chick weight and chick length were attained

from large egg size of broiler breeder hen. Egg size (51 to 68.85g) had no influence

on chick yield. However, chick yield were improved with extra-large egg size (>70

g) of breeder hen.

4.4.6 Effect of Broiler Breeder Age on Chick Quality

The effect of broiler breeder age on chick weight, chick yield and chick length

in commercial Hubbard Classic broiler breeder flock is shown in Table 4.12.

Breeder age had a significant (p≤0.05) effect on chick weight and chick length.

However, it was observed that age in broiler breeder had non-significant (p≥0.05)

effect on chick yield (male and female chick). The results revealed that chick weight

137

and chick length were improved significantly (p≤0.05) with advancing the age of

broiler breeder.

The results of the present experiment are agreed with other studies. In one

study, chicks that hatched out from the eggs of old broiler breeder flocks were usually

heavier, larger in size and of good quality because they had more resistant to

dehydration when compared to small-sized chicks hatched from young broiler

breeder flocks (Sinclair et al. 1990). Tona et al. (2004) reported that chick weight

increased with advancing age of breeders and the data showed that chick weight at

35 and 45 weeks of age in Cobb broiler breeder was found as 45.32 and 48.0 g,

respectively. These values were high than the present study at the same age of

breeder. This might be due to different strains used in both studies. Alsobayel et al.

(2013) presented a cumulative data of three broiler breeders (Arbor Acres, Cobb and

Ross) which indicated that hatched chicks’ attained weight as 41.4, 44.9 and 48.4 g

at 30-35, 40-45 and 50-55 weeks of breeder age. These workers also reported that

Cobb ranked first in chick weight (45.4 g) with advancing age of breeders followed

by Ross (44.9 g) and Arbor Acres (44.5 g). However, in the present study, hatched

chicks of Hubbard Classic breeder strain had more weight at any age of breeder than

those of Arbor Acres, Cobb and Ross mentioned in the above study. In another study,

maximum chick weight (51 vs. 40.3 g) was accomplished in 59 weeks old Ross-38

breeders as compared to young breeder at 40 weeks of age (Vieira et al., 2005).

Similarly, Ulmer-Franco et al. (2010) reported that more chick weight (48.9 vs.

37.3g) achieved from 59 weeks old Cobb breeder flock than that of 29 weeks old

flock. A similar trend was observed in the present experiment, maximum chick

weight (48.00 vs. 39.61g) was attained in 60 weeks old Hubbard breeder compared

to 30 weeks old breeder.

Contrary to above studies, Trehan and Bajwa (2001) did not observe any

significant difference in chick weight of 42 and 50 weeks old breeders. Similar results



138

were reported in quail, Yildirim and Yetisir (1998) found that the parental age had

non-significant (p≥0.05) effect on the hatch weight in Japanese quails at 22 and 65

weeks age. Similar findings were reported for quail chicks produced by 10 and 20

weeks old hens (Seker et al., 2004).

Decuypere and Bruggeman, (2007) reported that total chick length was

increased about 5% (from 19 to 20 cm) for breeders from 25 to 60 weeks of age.

Whereas, in the current study, 11% chick length was increased in both male and

female from 30 to 60 weeks of age in Hubbard broiler breeder strain.

Alsobayel et al. (2013) studied the effect of broiler breeder strain and age on

chick yields. They concluded that Ross had highest chick yield 69.7% followed by

Cobb (69.5%) and Arbor Acre (68.1%). They also concluded that older broiler

breeder flock (50-55 week) had highest (p≤0.05) chick weight percentage (69.7%)

compared to middle aged 40-45 week old (68.7%) and young aged 30-35 week old

(68.9%) broiler breeder. The present study shows that chick yield (69.83%) observed

in Hubbard classic strain is higher than Ross (69.7%), Cobb (69.5%) and Arbor Acre

(68.1%) in the previous study. Similarly, in the current study, at 30, 45 and 60 week

of age observed chick weight percentage (chick yield) were 69.68, 69.68 and 70.11%

respectively were close to above study. These differences in chick yields might be

the results of strain difference.

It is concluded that chick weight and chick lengths improved significantly

(p≤0.05) with advancing of age in broiler breeder hen but the effect of age on chick

yield is non-significant (p≥0.05).

139

Table 4.12: Effect of broiler breeder age on chick quality (Means± SE)

Parameters

Age (Weeks)

SEM P-

Value 30 45 60

Eggs set (No.) 100 100 100 - -

Egg weight

(g) 56.05b±1.46 65.03a±1.44 68.92a±1.69 1.358 0.000

Chick weight

(g)

Male 40.07b±2.04

45.46ab±2.12 48.03a±2.61 1.617 0.121

Female 39.16b±2.00

45.18ab±2.09 47.97a±2.62 1.701 0.085

Chick

yield*(%)

Male 70.17±0.33 69.90±0.05 70.19±0.11 0.092 0.417

Female 69.20±0.48 69.46±0.07 70.04±0.10 0.209 0.270

Chick length

(cm)

Male 18.07c±0.18

19.44b±0.22 20.32a±0.24 0.346 0.001

140

Female 17.96c±0.10

19.30b±0.17 20.35a±0.26 0.35554 0.000



Chapter 5

EFFECTS OF EGG SIZE (WEIGHT) AND AGE ON POST

HATCHING PERFORMANCE OF BROILER BREEDER

5.1 INTRODUCTION

Poultry, especially the broilers are the fastest converters of crude nutrients

into high quality animal protein that helped to overcome the shortage of protein from

animal origin. Broiler producers are faced with inconsistencies in the quality of day-

old chicks in several developing countries like Pakistan. The time taken for a broiler

to grow to market weight is decreasing with the passage of time due to genetic

improvement in broiler strains and improvement in the quality of poultry feed. In

1957, a broiler strain attained market weight (1.4 kg) in 84 days (Havenstein et al.,

2003); it currently takes 40 days for a broiler to reach 3 kg market weight (Leeson,

2012).

141

Several factors, directly or indirectly, affect the chick quality and subsequent

growth performance. There is evidence that egg size affects subsequent productivity

of layer and broiler chickens (Tuft and Jensen, 1991; Wyatt et al., 1985; Rashid et

al., 2005; Sklan et al., 2003; King’ori et al., 2007). Egg size in general, influences

broiler growth in a positive, linear manner (Gardner, 1973; Sinclair et al., 1990;

Schmidt et al., 2003). Egg size of broiler breeder hens increased with flock age (as

concluded in previous chapter). Although there is an indication that as birds age, the

effect of egg size diminishes (Leeson and Summers, 1989). Any effect of egg size on

post-hatch performance of broiler chicks has an important economic impact;

attention has been given to this subject since last century (Wiley, 1950; Pinchasov,

1991). Although a very close

121

correlation between egg and hatching weights has been reported (Abiola et al., 2008;

Vieira et al., 2005), effect on post hatching growth and broiler market weights are

variable. A number of workers have shown that egg size is an important factor in the

performance of broiler chicks to market weight (Wyatt et al., 1985; Abiola et al.,

2008), while others have found that any advantage of chicks hatched from large-sized

eggs diminishes rapidly after hatching

(Yannakopoulos and Tserveni-Gousi, 1987; Pinchasov, 1991; Egbeyale et al., 2011).

While Hearn (1986) suggested that segregation of hatching eggs according to weight

before incubation and separate rearing of day-old chicks of various weights resulted

in optimum growth and minimum variability of final market weight in broiler chicks.

A study of Alabi et al. (2012) showed that Potchefstroom Koekoek chicks

hatched from large-sized eggs had higher daily live weight gain and live body weight

at seven weeks than those hatched from medium and small-sized eggs. Those hatched

from medium-sized eggs also, had higher daily live weight gain and live body weight

http://www.researchgate.net/researcher/33333335_A_L_Yannakopoulos/



http://www.researchgate.net/researcher/5053931_A_S_Tserveni-Gousi/




http://www.researchgate.net/researcher/4620388_Y_Pinchasov/

142

at seven weeks than those from small-sized eggs. A similar trend was observed with

daily intake per bird. Chickens hatched from large-sized eggs had better feed

conversion ratio than those hatched from smallsized eggs although similar ratio was

observed between large and mediumsized eggs. The growth response of males to egg

weight is greater than that of females (Joubert et al., 1981). Tufft and Jesen (1991)

reported that the effect of the egg size on body weight of broiler at market age was

independent of the age of the breeders from which the eggs were obtained. The age

of broiler breeder was found to influence the performance of broiler differently

during the various phases of the growing period (Peebles et al., 1999). In addition,

results showed that market live weight of broilers from 51 week old broiler breeders

was significantly higher than that of broilers from 63 week old breeders. Conversion

of feed into live body weight by growing broilers did not appear to be directly related

to their egg size of origin. A portion of the body weight gain attributable to birds

from large eggs may be associated to their related increased feed intake (Pinchasov,

1991).

Due to paucity of information on post-hatching performance of Hubbard

broiler breeder, the present study is designed to determine the effect of egg size and

age on post hatching performance of Hubbard Classic broiler breeder strain.


5.2.1 Effects of Egg Weight of Broiler Breeder on Broiler Production

Parameters (Feed Intake, Live Body Weights and Feed Conversion

Ratio)

Alabi et al. (2012) studied the effect of egg weight on subsequent performance of

Potchefstroom Koekoek broiler chicks. A total of 450 hatching Potchefstroom

Koekoek chicken eggs obtained from the Agricultural Research Council (ARC),

Irene, Pretoria were used in this study. The study was divided into two parts. In both

parts, a complete randomized design was used. In first part of the study the eggs were

143

classified into three treatment groups as large (>55g), medium (45-55g) and small

(<45g), replicated three times. In the second part of the study, 80 chicks per group

were randomly selected from each hatched treatment for subsequent growth trial.

Each treatment was divided in four replicates with 20 chicks per replicate, thus a total

of 12 floor units (1.5 m2) were used in total. The experiment was conducted for 13

weeks. The results indicated that chicken hatched from large sized eggs had higher

(p≤0.05) daily live weight gain and live body weight at seven weeks than those

hatched from medium and small sized eggs. Those hatched from medium sized eggs

also had higher (p≤0.05) daily live weight gain and live weight at seven weeks than

those from small sized eggs. A similar trend was observed with daily intake per bird.

Chickens hatched from large sized eggs had better (p≤0.05) feed conversion ratio

than those hatched from small sized eggs although similar ratio was observed

between large and medium sized eggs. He further extended the study period to 13

weeks of age and concluded that chickens hatched from large sized eggs had higher

(p≤ 0.05) daily live weight gain, daily feed intake and live weight gain at 13 weeks

than those from medium sized eggs. Similarly chickens hatched from medium sized

eggs had higher (p≤0.05) daily live weight gain, daily feed intake and live weight

gain at 13 weeks than those hatched from small sized eggs. The feed conversion ratio

between eggs hatched from large and medium sized eggs were similar, however,

chickens hatched from large sized eggs had better (p≤0.05) feed conversion ratio

when compared to those hatched from small sized eggs.

Hearn (1986) conducted a study on broiler chicks hatched from the eggs of

different sizes and reared them till market weight. He concluded that if the hatching

eggs were separated by size (weight) in the hatchery and the chicks were reared

separately, variability at slaughtering age would be minimized and the growth of each

group will be optimum.

144

Ulmer-Franco et al. (2010) studied the effect of egg weight on broiler

performances. At hatchery the eggs were categorized into low, medium and heavy

weight before incubation. Day-old chicks hatched from each category were reared

separately till 7 week of age. It was observed that there were significant (p≤0.05)

differences in early, late and final live market body weight gains among egg size

treatment groups. Broilers hatched from largest eggs had heaviest live weight

(p≤0.05) at 21 day. In spite of differences in day-old chick weight at hatching,

broilers hatched from light and average eggs had non-significant (p≥0.05) in body

weight at

21 day. Even though, broilers from heavy eggs at market age were heavier (p≤0.05)

than those from light eggs, while broilers from average eggs had caught up in body

weight with those from heavy eggs. Although at hatching, chicks from average eggs

were approximately3.5 g lighter than chicks from heavy eggs and 3.1 g heavier than

chicks from light eggs approximately. At hatching, heavy chicks were 6.6 g heavier

than lighter chicks, perhaps a large enough difference to affect final market live body

weight. Finally, they concluded that day-old chick weight was not an accurate

predictor of final body weight in broiler chicks. They further investigated that egg

weight had not any effect on feed consumption or FCR parameters in broilers.

Abiola et al. (2008) conducted a study to evaluate the effect of egg size on

broiler production parameters. A total of 198 hatchable Anak broiler eggs comprising

of small (40g average weight), medium (50g average weight) and large (60g average

weight) size categories were obtained from a commercial hatchery for the study.

Results of post hatch performance of the chicks in the starter phase showed a positive

correlation between egg size and chick hatching weight. Small chicks hatched from

small eggs while large chicks hatched from large eggs. The chicks maintained their

size categories up to the end of the starter phase. Values obtained for daily weight

145

gain for the 3 categories of chicks were comparable with one another. However, daily

feed intake increased with increase in the weight of chicks, values obtained ranged

from 30.75 to 50.08 g/bird. Expectedly the larger chicks had the highest average daily

feed intake of 50.08 g/bird but recorded the poorest value of 2.54 feed conversion

ratios. At the end of the finisher phase the large birds maintained the advantage of

their initially higher egg weight thereby resulting in the highest average live weight

of 1510 g /bird. Results recorded for medium and large chicks on weight gain are

similar to one another while small chicks had the lowest average daily weight gain

of 29.34 g/bird. They concluded that there was inverse relationship between feed

intake and chick weight in the finisher phase. Daily feed intake decreased with

increase in the weight of chicks. The large chicks had the lowest average daily feed

intake of 113.07 g/bird. So advantage of initially higher chick weight related to large

egg size diminishes rapidly after hatching.

Tufft and Jensen (1991) reported that egg weight had significant (p≤0.05)

effect on subsequent chicks’ performance of broiler chickens. They further

concluded that effect of the egg weight on body weight of broiler chicks at market

age has been found to be independent of the egg size of the broiler breeders.

Ng’ambi et al. (2013) conducted a study to see the effect of egg weight on

subsequent productivity of indigenous Venda chickens. A total of 360 hatching eggs

were collected and distributed into four categories entirely at random. Each treatment

had 90 eggs. The egg weights were as follows: below 49 g, from 50 to 59 g, from 60

to 69 g and above 70 g. Day-old chicks hatched from each egg category were reared

separately. They concluded that at market weight, growth rate and live body weight

of the chickens were optimum when egg weights were of 56 (r2= 0.657) and 60 (r2=

0.870) g respectively, for chickens aged 1 to 7 weeks, and egg weights of 61 g (r2=

146

0.514) and 60 g (r2= 0.948) were optimum for chickens aged 8 to 13 weeks. They

concluded that production variables were optimized to different egg weights.

Whyatt et al. (1985) conducted an experiment to study the effect of egg size

on broiler performance. Hatching eggs from commercial broiler breeders with similar

genetic backgrounds were distributed into two egg weight categories (47 to 57 g and

58 to 66 g). After all dry chicks hatched out from each egg size category were

removed, and then placed into floor pens (experiment units) and reared till 7 week of

age. They concluded that the broilers hatched from larger eggs were significantly

heavier (2080 vs 1889g) and had better livability than those from small eggs through

49 days of age. Furthermore, chicks hatched from small eggs had better feed

efficiency than those from large eggs at 49 days of age.

5.2.2 Effects of Age of Broiler Breeder on Broiler production Parameters (Feed

Intake, Live Body Weights and Feed Conversion Ratio)

Ulmer-Franco et al. (2010) conducted a study on the broilers hatched from

the 29 and 59 week old broiler breeders. They concluded that body weight at 21 day

(early) and 41 day (final) as well as early and overall body weight gains were

significantly (p≤0.05) lowers in chicks hatched from the young breeder flock age

than the chicks hatched from the older flock age.

They further investigated that there were non-significant (p≥0.05) differences in

early, late, or overall feed conversion ratio among the broilers hatched from the

broiler breeder flocks at different ages. So regardless of breeder flock age, Cobb

broilers had the same feed conversion ratio

potential.

Hulet et al. (2007) compared the cumulative the feed conversion ratios (up to

44 day of age) of broiler chicks hatched from 57 week old vs. 29 week old broiler

breeder flocks of Cobb 500 strain. Even though the biggest chicks (those hatched

147

from 57 week old flock) were heavier throughout growing period, but they were less

efficient (higher FCR) than the chicks from the young flock (29 week old).

Peebles et al. (1999) also studied the effects of broiler breeder age (35, 51,

and 63 week) on broiler performance. They reared broilers for 42 days to measure

growth, mortality and feed conversion ratio. They observed that broilers from hens

at 35 week of age are better efficient between 0 and 21 days than those from 51

and 63 week old hens. Conversely, between 22 and 42 days, broilers from hens 51

week of age are better efficient than those at 35 and 63 week. In conclusion, breeder

age influenced broiler performances differently throughout grow out period.

On contrary, Mc Naugton et al. (1978) studied the effect of breeder age and

hatching egg weight on body weight gain. A total of 7400 mixed-sex broilers were

used in each experiment. A total of 925 day-old chicks were housed, hatched from

hen eggs weighing 47-54 and 57-62 grams when broiler breeder age was 29 week.

Similarly, 925 chicks were housed hatching from hen eggs weighing 57-62 and

6774 grams at 58 week of age. Higher market broiler live body weights were

observed for the chicks hatched from the heavier egg groups compared to chicks

hatched from small-sized eggs. They concluded that age of broiler breeder had

nonsignificant (p≥0.05) effect on live market body weights of broilers.

5.2.3 Effects of Egg Weight and Age of Broiler Breeder on Broiler Mortality

Mortality of broilers during growth period due to different reasons are of great

importance, not only because of the feed loss which was consumed by the dead birds

but also because of the money losses resulting from retarded growth and inferior meat

value.

Ulmer-Franco et al. (2010) conducted a study to observe the effect of age (29

vs 59 weeks) and egg weight (low, medium and heavy weight) on broiler mortality

percentages. At hatchery the eggs were categorized into low, medium and heavy

148

weight before incubation. Day-old chicks hatched from each category were reared up

to 7 week of age. They concluded that the effects flock age and egg weight on broiler

mortality were non-significant (p≥0.05).

Alabi et al. (2012) studied the influence of egg weight on subsequent

mortality rates in Potchefstroom Koekoek chicks. A total of 450 hatching

Potchefstroom Koekoek chicken eggs obtained from the Agricultural Research

Council (ARC), Irene, Pretoria were used to determine the effect of egg weight on

mortality rates. The study was divided into two parts. In both parts, a complete

randomized design was used. In first part of the study the eggs were distributed into

three treatment groups as large (>55 g), medium (45-55 g) and small (<45 g),

replicated three times. In the second part of the study, 80 chicks per group were

randomly selected from each hatched treatment for subsequent growth trial. Each

treatment was divided in four replicates with 20 chicks per replicate, thus a total of

12 floor units (1.5 m2) were used in total. The experiments were conducted for 13

weeks and it was concluded that egg size had non-significant effect (p≥ 0.05) on

chicken mortality rates between 1 and 13 weeks of age.

Ng’ambi, et al. (2013) conducted a study to determine the effect of egg weight

on mortality rates in broiler chicken. A total of 360 eggs were collected and

distributed into four egg weight categories. The four egg weights were as follows:

below 49 g, ranging from 50 to 59 g, ranging from 60 to 69 g and above

70 g. Day-old chicks hatched from each egg category were reared separately. They

concluded that at market weight, chicks hatched from heavier sized eggs had higher

mortality rates.

Mc Naugton et al. (1978) conducted 2 studies to evaluate the effect of breeder

age and hatching egg weight on broiler chick mortality in broiler breeders.

149

A total of 7400 mixed-sex broiler chicks were used in each experiment. A total of

925 chicks were housed, hatched from hen eggs weighing 47 to 54 and 57 to 62 grams

when broiler breeder age was 29 week. Similarly, 925 chicks were housed, hatched

from hen eggs weighing 57 to 62 and 67 to 74 grams at 58 week of age. Higher

mortality percentage occurred in the chicks that were hatched from the eggs of 29

week old broiler breeder as compared to the chicks hatched from the eggs of 58 week

old breeders. Also, higher mortality rates occurred in chicks hatched from eggs

weighing 47-54 grams compared to the eggs either 57 to 62 or 67 to 74 gram.

Yassin et al. (2009) conducted a study to observe first week mortality rates in

broilers. Two commercial Dutch hatcheries provided the data of 482 broiler farms

who voluntarily recorded the first week mortality rates of 16,365 flocks of broiler

chicks for the years 2004, 2005, and 2006. The data represented the 79% of the total

number of day-old chicks delivered to separate broiler farms. They concluded that

first week mortality rates in broilers significantly relate to broiler breeder age, egg

storage duration and conditions, season and strain, feed manufacturing company of

the breeder farm, year and hatchery. They further investigated that first week

mortality rates differed significantly between chicks hatched from eggs of different

breeder flocks.


5.3.1 Selection of Day-old Chicks, Experimental Site and Rearing Conditions

These trials were conducted in a commercial semi-controlled shed, located at

Tumair village, Islamabad with the permission of Chairman and

Dean of Faculty of Veterinary and Animal Sciences, Pir Mehr Ali Shah, Arid

Agriculture University, Rawalpindi. The shed was divided into 18 pens

(Experimental units) by a partition each measuring 5×3×10 feet (L×W×H). The shed

150

was cleaned, disinfected and fumigated before arrival of day-old chicks. A 2-3 inch

thick layer of rice husk was used as litter material in each pen.

At each stage of production period (30, 45 and 60 week), 90 day-old chicks

(45 males and 45 females) from each egg category (small, medium and large size)

were selected entirely at random from Rose hatchery. These 45 male and 45 female

day-old chicks from each egg size category were replicated thrice, each having 15

day-old chicks and shifted to a commercial semi-controlled shed located at Tumair

village, Islamabad. These replicated day-old chicks were allotted randomly into 18

experimental units of shed. During brooding and growing period, the chicks were

provided temperature, humidity, ventilation rate etc. as per brooding and growing

requirements. The brooding temperature was maintained at 32 °C till 5 days of age

and then gradually decreased to 25 °C by 21st day of age, after which the chicken

were kept at room temperature. Space diesel heater was used to maintain the shed

required temperature. Relative humidity was recorded and ranged between 50 to 60%

during brooding and growing periods. Twenty four hours light period (during first

week) twenty two hours light period (during second, third and fourth week) while

during last week (5th week) twenty four hours light period was provided to the chicks.

The birds were vaccinated against ND, IB and IBD diseases (according to local

broiler vaccine schedule). Aantibiotics (Tylosine, doxycycline and colistine) were

provided as a preventive measure during rearing periods. Fresh water and good

quality feed was provided to chicks at libitum. The chicks were provided with ½

square foot floor space during the first 3 weeks of age and then 1 square foot floor

space till the termination of the trial. The birds were provided with commercial

broiler starter diet (0-10 days), broiler grower diet (1125 days) and boiler finisher

diet (from 26 to 35 days of age). Composition of experimental diets is given in Table

151

5.1, 5.2 and 5.3. The experiment was continued for 5 weeks. The plan of study is

given in Table 5.4. The following parameters were recorded on weekly basis:

5.3.2 Measured Parameters

5.3.2.1 Day-old Chick’s Weight

Immediately after arrival of day-old chicks at the farm, chicks were weighed

by an electronic balance to record the average day-old weight for male Table 5.1:

Composition of broiler starter diet (1-10 days)

Ingredients

Quantity

(g/kg) Ingredients

Quantity

(g/kg)

Maize 507.07 Lysine sulphate 5.08

Rice polish 120.00 DL-Methionine 2.13

Wheat bran 4.16 Threonine 0.74

Corn gluten meal-60 10.00 L-Tryptophan 0.07

SBM Hydro (48%CP) 180.73 Betain HCl 1.30

Sun flower meal 80.00 L-Valine 0.28

Guar meal 20.00 Phytase 100 pure(1000) 0.10

Rape seed meal 20.00 Vitamin premix2 1.00

Canola meal 15.38 Mineral premix1 0.40

Marble chips 6.16

Maduramicine

Ammonium 0.60

Bone meal 20.30 Eneramycin (4%) (AGP) 0.12

Salt 3.26 Antioxidant 0.12

Sodium Bi Carbonate 1.00 Total 1000

Calculated Analysis



152



Ash (%) 6.05

Methionine+Cystine

(Dig)(%) 0.77


Phosphorus

(Available) (%) 0.43 - -

1Provided the following per kilogram of diet: Vitamin A (as retinyl acetate), 15000 (IU);

cholecalciferol, 3000 (IU); vitamin E (as dl-α-tocopheryl acetate), 50 mg; vitamin B12,0.02

mg; riboflavin, 8.0 mg; d-calcium pantothenic acid, 15.0 mg; niacin, 60 mg; choline, 700

mg; folic acid, 1.5 mg; vitamin B1 (thiamin mononitrate), 3.0 mg; pyridoxine, 4.0 mg;

biotin, 0.2 mg; vitamin K (menadione sodium bisulfate complex), 3.0 mg. 2Provided the following per kilogram of diet: manganese sulphate, 80.0 mg; copper

sulphate, 10 mg; zinc sulphate, 80 mg; selenium, 0.2 mg; potassium iodide, 1.0 mg

Table 5.2: Composition of broiler grower diet (11-25 days)

Ingredients

Quantity

(g/kg) Ingredients

Quantity

(g/kg)



Corn gluten meal-60 10.00 Threonine 0.72


Sun flower meal 87.24 Betain HCl 1.30

Guar meal 20.00 L-Valine 0.28

Rape seed meal 20.00 Phytase 100 pure(10000) 0.10

Fish meal 30.00 Vitamin premix2 1.00

Marble chips 7.57 Mineral premix1 0.40

1 Provided the following per kilogram of diet: Vitamin A (as retinyl acetate), 12500 (IU);

cholecalciferol, 2500 (IU); vitamin E (as dl-α-tocopheryl acetate), 30 mg; vitamin B12,0.01 mg;

riboflavin, 6.0 mg; d-calcium pantothenic acid, 10.0 mg; niacin, 40 mg; choline, 600 mg; folic

acid, 1.0mg; vitamin B1 (thiamin mononitrate), 2.0 mg; pyridoxine, 3.0 mg; biotin, 0.1 mg;

vitamin K (menadione sodium bisulfate complex), 2.0 mg. 2Provided the following per

kilogram of diet: Manganese sulphate, 80.0 mg; copper sulphate, 10 mg; zinc

sulphate, 80 mg; selenium, 0.2 mg; potassium iodide, 1.0 mg

153

Bone meal 8.69

Maduramicine

Ammonium 0.60

Salt 1.81 Eneramycin (4%) (AGP) 0.12

Sodium Bi Carbonate 1.00 Antioxidant 0.12

- - Total 1000

Calculated Analysis





Ash (%) 5.76

Methionine+Cystine

(Dig)(%) 0.74


Phosphorus

(Available) (%) 0.40 - -

Table 5.3: Composition of broiler finisher diet (26-35 days)

Ingredients

Quantity

(g/kg) Ingredients

Quantity

(g/kg)



Corn gluten meal-60 10.00 Threonine 0.87


Sun flower meal 87.24 Betain HCl 1.30

Guar meal 20.00 L-Valine 0.03

Rape seed meal 28.51 Phytase 100 pure(10000) 0.10

Fish meal 30.00 Vitamin premix2 1.00

Marble chips 7.50 Mineral premix1 0.06

1 Provided the following per kilogram of diet: Vitamin A (as retinyl acetate), 10000 (IU);

cholecalciferol, 2000 (IU); vitamin E (as dl-α-tocopheryl acetate), 30 mg; vitamin B12,0.01 mg;

154

Bone meal 9.68

Maduramicine

Ammonium 0.60

Salt 1.35 Eneramycin (4%) (AGP) 0.12

Sodium Bi Carbonate 1.00 Antioxidant 0.12

- - Total 1000

Calculated Analysis





Ash (%) 5.03

Methionine+Cystine

(Dig)(%) 0.72


Phosphorus

(Available) (%) 0.40 - -

Table 5.4: The plan to study the effect of egg weight, age and broiler sex on broiler

production parameters

Major

treatment

(Flock age) Sub treatment

(Egg category) Sex

No of

replicate per

sub treatment No of replicate groups

Chicks

per

replicate

Total

chicks

per sub

treatment

A (30 week)

AA (Small size)

M* 3 MAA1, MAA2, MAA3 15 45

FM** 3 FAA1, FAA2, FAA3 15 45

AB (Medium size)

M* 3 MAB1, MAB2, MAB3 15 45

FM** 3 FAB1, FAB2, FAB3 15 45

AC (Large size) M* 3 MAC1, MAC2, MAC3 15 45

riboflavin, 6.0 mg; d-calcium pantothenic acid, 1.0 mg; niacin, 40 mg; choline, 600 mg; folic

acid, 1.0mg; vitamin B1 (thiamin mononitrate), 2.0 mg; pyridoxine, 3.0 mg; biotin, 0.1 mg;

vitamin K (menadione sodium bisulfate complex), 2.0 mg. 2Provided the following per

kilogram of diet: Manganese sulphate, 80.0 mg; copper sulphate, 80 mg; zinc

sulphate, 80 mg; selenium, 0.2 mg; potassium iodide, 1.0 mg

155

FM** 3 FAC1, FAC2, FAC3 15 45

B (45 week)

BA (Small size)

M* 3 MBA1, MBA2, MBA3 15 45

FM** 3 FBA1, FBA2, FBA3 15 45

BB (Medium size)

M* 3 MBB1, MBB2, MBB3 15 45

FM** 3 FBB1, FBB2, FBB3 15 45

BC (Large size)

M* 3 MBC1, MBC2, MBC3 15 45

FM** 3 FBC1, FBC2, FBC3 15 45

C (60 week)

CA (Small size)

M* 3 MCA1, MCA2, MCA3 15 45

FM** 3 FCA1, FCA2, FCA3 15 45

CB (Medium size)

M* 3 MCB1, MCB2, MCB3 15 45

FM** 3 FCB1, FCB2, FCB3 15 45

CC (Large size)

M* 3 MCC1, MCC2, MCC3 15 45

FM** 3 FCC1, FCC2, FCC3 15 45

*M= Male

**FM=Female

and female broiler chicks of each egg size category. The weight was measured in

grams. After weighing, day-old chicks were distributed into experimental units

(replicates) entirely at random.

5.3.2.2 Body Weight

At the end of each week, all the chicks in each replicates were weighed by an

accurate electronic scale to measure the average body weight (g) for male and female

broiler chicks of each egg size category. Cumulative live body weight (g) for each

replicate was also calculated at the completion of each week till the termination of

experiment.

156

5.3.2.3 Feed Consumption

The feed consumed by the all chicks in each replicate group was measured on

weekly basis by using an accurate electronic scale to measure the average feed

consumption (g) for male and female broiler chicks of each egg size category.

Cumulative feed consumed (g) for each replicate was calculated at the completion of

each week till the end of experiment.

5.3.2.4 Feed Conversion Ratio

Weekly feed conversion ratios for male and broiler chicks of each replicate

were measured by the following formula

Cumulative feed conversion ratio for each replicate was calculated at the

completion of each week till the end of experiment.

5.3.2.5 Mortality

Weekly mortality percentage for male and broiler chicks of each replicate

were also recorded during rearing period. Cumulative mortality (%) for each

replicate was also calculated at the termination of experiment.


Data were evaluated using Two-way ANOVA and analyzed using GLM (General

Linear Model) procedures of SPSS 16.0 software. When differences were significant,

means were compared using Duncan’s Multiple Range tests at the 0.05 level of

significance.

157


5.4.1 Effect of Hatching Egg Size on Post-Hatch Chick Growth

The influence of egg size on growth of post-hatch broiler chicks derived from

broiler breeder flock at an early (30 week) stage of production period is shown in

Table 5.5. At this stage of production period, egg size had significant

(p≤0.05) effect on day-old and weekly chick weights. It was observed that chick

weight at day-old, second and third weeks of growth was significantly (p≤0.05)

increased with increasing the egg size. However, non-significant difference

(p≥0.05) was found in chick weight of different egg size groups at first, fourth and

fifth weeks of growth. Generally, it was examined that average live body weight of

both sexes (male and female broiler chicks) increased with increasing the egg size

but the effect of egg size on chick weight becomes insignificant (p≥0.05) from 4 th

week of age. However, chicks hatched from the large-sized eggs (average weight

61.06g) attained numerically maximum weight (1546g) at 35 day of growing period

than small and medium -sized eggs (1540 and 1545g respectively).


broiler breeder flock at mid (45 week) stage of production period is given in Table

5.6. At this stage of production period, egg size had significant (p≤0.05) effect on

day-old weight. Moreover, egg size had also significant (p≤0.05) effect on female

weights at second and third weeks of growth. It was recorded that chick weight at

day-old and female chick weight at second and third weeks of growth was

significantly (p≤0.05) increased with increasing the egg size. Generally, it was

observed that average live body weight of both sexes (male and female) are affected

by the egg size but the effect of egg size on chick weight becomes insignificant

(p≥0.05) from 4th week of age. However, the chicks hatched from the small and

medium-sized eggs (average weight 60.05 and 65.10g respectively) attained

158

numerically maximum weight (1557g) at 35 day of growing period than large-sized

eggs (1552g).


broiler breeder flock at late (60 week) stage of production period is shown in Table

5.7. At late stage of production period, egg size had significant (p≤0.05) effect on

day-old weight. Moreover, egg size had also significant (p≤0.05) effect on male chick

weights at first week and the live body weight of both sexes (male and females) at

second and third weeks of growth period. However, non-significant difference

(p≥0.05) was found in chick weight of different egg size groups at fourth and fifth

weeks of growth period. Generally, it was observed that average live body weight of

both sexes (male and female) decreased with increasing the egg size but the effect of

egg size on chick weight becomes insignificant (p≥0.05) from 4 th week of age.

However, the chicks hatched from the small-sized eggs (average weight

63.09g) attained numerically maximum weight (1553g) at 35 day of growing period

than medium and large-sized eggs (1551 and 1545g respectively).

The previous studies on the influence of egg size (weight) on the performance

of broilers has shown variable results, mainly because it is difficult to control all the

factors affecting the performance of broiler chickens. It has been proved that day-old

chick weight is affected by egg weight, as the hatched out chick is approximately

65% of egg weight (Wilson and Harms 1988). Some studies in broiler quail indicated

that hatching egg size, chick weight and chick growth were interrelated (Farooq et

al., 2001 and Petek et al. 2003). The correlation between egg size and body weight

of hatched broiler chicks from the 5th to the 8th week of age is significant in many

broiler meat lines and may vary from 0.3 to 0.5

(Joubert et al., 1981; Whiting and Pesti, 1984; Wyatt et al., 1985; Hearn, 1986).

Studies showed that high correlation was found between egg size and day-old chick

159

weight in different domestic birds (Shanawany, 1987; Pinchasov, 1991; Dudusola,

2013). The initial weight of the chicks was significantly (p≤0.05) increased by the

egg size. These results are in order with the present study. Chick weight at hatching

followed the same pattern as the egg weight at setting. Thus, lightest chicks hatched

from small eggs produced by the young flock and the heaviest chicks hatched from

the large eggs produced by the old flock.

In the current experiments, regardless of stage of production period, the

growth of chicks in the first three weeks was influenced by egg size but by the fourth

week, this effect disappeared. This agrees with previous reports (Sharma et al., 1985;

Sinclair et al., 1990; Tuff and Jensen, 1991) that indicate that the

Table 5.5: Effect of broiler breeder egg size on post-hatch broiler chick weight at

early (30 week) stage of production period (Means± SE)

Factors Egg size

SEM P-value Small Medium Large

No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Day old weight

(g)

Male 36.1c±0.2 39.4b±0.3 43.3a±0.8 1.069 0.000

Female 35.6c±0.3 38.5b±0.5 42.4a±0.2 0.994 0.000

Weekly weight

(g)

First

Male 141.2±1.6 142.2±5.0 145.7±3.2 1.897 0.659

Female 140.3±3.5 144.3±0.6 141.7±1.9 1.302 0.500

Second

Male 403.3b±2.3 409.4ab±2.2 412.5a±3.0 1.845 0.100

Female 393.0b±3.4 398.4ab±1.6 402.2a±0.8 1.731 0.068

Third

Male 686.7b±1.7 692.1ab±3.6 697.4a±2.0 2.021 0.070

Female 673.4b±2.3 678.8ab±2.5 687.2a±2.5 2.343 0.020

Fourth

160

Male 1078.3±1.7 1082.3±6.5 1091.7±3.8 0.969 0.173

Female 1048.7±4.7 1059.3±5.8 1063.3±2.33 3.174 0.130

Fifth

Male 1553.7±6.8 1577.0±19.6 1573.3±10.0 7.568 0.458

Female 1525.7±17.2 1513.0±7.0 1519.3±6.7 5.981 0.745



mid (45 week) stage of production period (Means± SE)

Factors Egg size


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Day old weight (g)

Male 41.2a±0.4 44.5b±0.4 47.6c±0.1 0.939 0.000

Female 39.9a±0.5 43.2b±0.1 47.4c±0.2 1.091 0.000

Weekly weight (g)

First

Male 145.3±2.5 148.0±1.8 151.4±1.6 1.343 0.177

Female 145.9±0.6 145.6±2.7 146.7±1.9 1.000 0.921

Second

Male 405.4±1.0 403.9±1.9 412.8±5.0 2.078 0.180

Female 397.0a±1.8 402.1b±0.8 407.2c±0.7 1.598 0.003

Third

Male 686.7±1.7 688.7±2.7 690.3±1.9 1.187 0.519

Female 676.3a±2.4 678.8ab±2.5 684.8b±0.7 1.591 0.073

Fourth

Male 1083.3±6.0 1082.3±5.0 1078.7±4.0 2.651 0.800

Female 1057.7±1.4 1057.3±1.8 1060.7±2.3 1.081 0.439

Fifth

161

Male 1578.7±1.9 1584.3±2.3 1576.7±6.6 2.377 0.451

Female 1535.3±4.4 1529.0±1.5 1526.7±2.9 2.048 0.216



late (60 week) stage of production period (Means± SE)

Factors Egg size


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Day old weight (g)

Male 42.4a±0.1 47.0b±1.2 51.6c±0.1 1.322 0.000

Female 42.3a±0.1 46.9b±0.1 51.4c±0.1 1.3155 0.000

Weekly weight (g)

First

Male 152.4a±1.6 154.0ab±2.6 160.6b±1.6 1.595 0.058

Female 151.3±2.5 156.9±1.5 157.4±0.6 1.298 0.081

Second

Male 408.6a±1.0 415.3ab±3.6 422.2b±4.3 2.564 0.071

Female 399.0a±2.8 405.8b±0.8 411.2b±0.6 1.962 0.007

Third

Male 686.7a±1.7 692.1ab±3.6 697.4b±2.0 2.020 0.070

Female 673.4a±2.3 678.8ab±2.5 684. 3b±0.8 1.8718 0.025

Fourth

Male 1083.3±6.0 1090.7±3.0 1091.7±3.8 2.577 0.406

Female 1048.7±4.7 1056.0±3.0 1059.0±1.0 2.249 0.153

Fifth

Male 1581.0±2.9 1577.0±3.6 1575.7±2.3 1.659 0.468

162

Female 1525.3±3.2 1526.0±5.2 1521.3±2.4 2.2026 0.660


correlation between egg size and chick body weight diminishes with increasing age

of the growing chick. It also correspond with Alabi et al. (2012), who studied the

effect of egg size on post-hatch performance of Potchefstroom Koekoek chicks from

one to seven weeks of age and found that chickens hatched from largesized eggs had

higher daily live weight gain and live weight at seven weeks than those hatched from

medium and small-sized eggs. Constantini and Panella (1984) also found that the

higher chick hatch-weights were result of higher nutrient content in larger eggs. In

commercial Leghorn breeder, it was noticed that upto 8 week of age, pullets hatched

from small-sized eggs were smaller (p≤0.05) than the chicks hatched from large-

sized eggs, and often smaller than chicks from mediumsized eggs (Leeson and

Summers, 1989). However, pullets from small eggs were small till 12 week of age,

although no effect on body weight gain was observed after this time (Leeson and

Summers, 1989). Proudfoot et al. (1982) estimated that an increase of one gram in

egg weight at time of incubation, affect body weight of hatched broiler chicks at 49

days, with gains of 8.9 and 7.6 g in males and females, respectively. In this

experiment, the growth response of males to egg size is greater than that of females.

These findings are harmony with findings of Joubert et al. 1981.

In all production stages, at fourth and fifth weeks of growing phase, the birds

from small and medium eggs were able to catch up with their counterpart at the end

of fifth week. This could be attributed to the numerically higher feed intake by the

163

two groups as compared to the large eggs group. One of the most important factors

affecting the growth rate in birds is feed intake (Ayanwale and Eyo, 2007).

The benefits of initially higher chick weight regarding to a large egg size diminishes

rapidly after hatching while feed intake is the major factor affecting final body weight

(Wyatt et al., 1985). However, the final weights of the birds at the end of the study

were statistically similar, the highest weight of chick from large egg may have

resulted from the influence of hatching egg size and this is in harmony with the

findings of Egbeyale et al. (2011) reported that average live weight of cockerels

(Dominant Black and Yaffa Brown strains of pullet) was heaviest in the large-sized

eggs than the other groups throughout the chicks phase.

However, the final weights of the birds from small, medium and large-sized eggs

(1242.91, 1287.49 and 1338.33 g, respectively) were statistically similar and this

confirmed the significance of big size-egg for incubation (Abiola et al., 2008).

In the present study, at all stages of production period, body weight at hatching,

chicks hatched from medium-sized eggs were approximately 3.3 g heavier than

chicks from small-sized eggs, and approximately 3.9 g lighter than chicks from large-

sized eggs. This result corroborates the findings of Ulmer-Franco et al. (2010), who

reported that at market age broilers from large-sized eggs were heavier than those

from small-sized eggs, broilers from medium-sized eggs had the same body weight

as from large-sized eggs. When looking back at body weight at hatching, chicks from

medium-sized eggs were about 3.1 g heavier than chicks from small eggs, and about

3.5 g lighter than chicks from large eggs. This means that heavy chicks were about

6.6 g heavier than light chicks at hatching, perhaps a large enough difference to affect

final market live body weight.

It is concluded that generally, it was observed that broiler weight increased

with increasing the egg size. Regardless of stage of production period, the growth of

164

chicks in the first three weeks was influenced by egg size but by fourth week, this

effect disappeared. Chicks hatched from the medium-sized eggs (60-65g) gained

numerically but non-significantly higher live body weight as compared to chicks

hatched from other egg sized groups at 5 week of age.

5.4.2 Effect of Breeder Age on Post-Hatch Chick Growth

The influence of breeder age on post-hatch chick growth in commercial

Hubbard Classic broiler breeder flock is shown in Table 5.8. Breeder age had a

significant (p≤0.05) effect on broiler growth from day-old to second week of growth.

The results revealed that chick growth was improved (p≤0.05) with advancing age of

broiler breeder from day one to day 14. However, age had no

(p≥0.05) influence on chick growth from third to fifth weeks of growing period.

The results of the present experiment are agreed with other studies. Onbaşılar

et al. (2008) reported that body weight gain and final body weight from fourth to

sixth weeks of age were similar (p≥0.01) among breeder age groups (32, 48 and 61

weeks). They also found that body weight gain of the first 3 week of rearing was

lower (p≤0.01) for broilers from younger breeders. Similarly, present study showed

body weight of younger breeder (30 weeks old flock) was lower from day-old to first

week of growth. Noble et al. (1986) reported that smaller eggs produced by young

broiler breeders (25 week) have been found to yield smaller chicks with longer

residual yolk sacks than breeders at 41 week. These results are further strengthened

by Ulmer-Franco et al. (2010), who reported that body weights at 21 day (early) and

41 day (final) as well as early and overall live body weight gains were significantly

lower in chicks hatched from the eggs of young breeder flock than those of chicks

hatched from the old broiler breeder. This could be associated to the lowest feed

consumption by the chicks hatched from the young Table 5.8: Effect of breeder age

on broiler live body weight (Means± SE)

165

Factors Broiler Breeder Age (Week)

SEM P-value 30 45 60

No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Day old weight (g)

Male 39.58b±1.0 44.44a±0.9 46.98a±1.3 0.866 0.000

Female 38.84c±0.9 43.49b±1.0 46.87a±1.3 0.904 0.000

Weekly weight (g)

First

Male 142.9c±1.9 149.2b±1.1 155.6a±1.6 1.33490 0.000

Female 142.1b±1.3 145.1b±0.9 155.2a±1.3 1.279 0.000

Second

Male 408.4b±1.8 407.3b±2.1 415.4a±2.6 1.398 0.032

Female 397.9b±1.7 402.2ab±1.6 406.4a±1.9 1.15074 0.022

Third

Male 692.0±2.0 688.6±1.2 692.0±2.0 1.042 0.162

Female 679.8±2.3 680.1±1.6 678.93±1.9 1.092 0.765

Fourth

Male 1084.1±2.9 1081.4±2.6 1088.6±2.6 1.624 0.198

Female 1060.1±4.2 1058.6±1.1 1054.6±2.2 1.629 0.337

Fifth

Male 1568.0±7.6 1579.9±2.4 1577.9±1.7 2.790 0.198

Female 1519.3±5.9 1528.6±2.6 1523.1±2.2 2.323 0.312


broiler breeders during the first 3 week of grow-out period. However, Peebles et al.

(1999) showed that age had a significant effect on broiler body weight gain between

0-3, 3-6 and 0-6 weeks of broiler age. They also found that broilers from hens at 35

week of age were lowest in body weight gain than those from 51 and 63 week of age.

166

These results are also in agreement with current study in which the chicks hatched

from young breeders (30 week) were lower in weight than from older breeders (45

and 60 week). In commercial Leghorn breeder, chicks hatched from old breeders

were heavier up to 3 week of age (p≤0.05), although there was no effect of breeder

age noticed after this period (Leeson and Summers, 1989).

It is concluded that generally, it was observed that chick growth was

improved with advancing age of broiler breeder from 1d to 14 d. However, age had

non-significant (p≥0.05) influence on chick growth from third to fifth weeks of

growing period.

5.4.3 Effect of Hatching Egg Size on Broiler Feed Intake

The effect of egg size on feed intake in chicks derived from broiler breeder

flock at an early (30 week) stage of production period is shown in Table 5.9. At this

stage of production period, egg size had non-significant (p≥0.05) effect on chick feed

intake during growth period except 3rd week of growth. It was observed that chick

feed intake was significantly (p≤0.05) increased with increasing the egg size at 3 rd

weeks of growth.


flock at mid (45 week) stage of production period is shown in Table 5.10. At this


intake during growth period except in females at 3rd week of growth. It was found

that female chick feed intake was significantly (p≤0.05) increased with increasing

the egg size at 3rd weeks of growth.


flock at late (60 week) stage of production period is shown in Table 5.11. At this


intake during growth period except in males at 3rd week of growth. It was observed

167

that male chick feed intake was significantly (p≤0.05) increased with increasing the

egg size at 3rd weeks of growth.

Limited literature is available regarding effect of egg size on feed intake in

broiler breeder. The results of current study are comparable with the findings of

Ulmer-Franco et al. (2010), who reported that egg size did not affect feed

consumption of commercial Cobb -500 broiler breeder flock. The data showed that

early feed consumption (1 d to 21 d) was found as 1024.2, 1030.7 and 1031.6 g/bird

for small, medium and large eggs, respectively. Similarly, late feed consumption (22

d to 41 d) was reported as 3060, 3154.3 and 3119.8 g/bird for small, medium and

large eggs, respectively. These values are high than the present study at the same

growth period that might be breed/strain difference. Similarly, a previous study also

supported that egg size had no influence on broiler breeder feed intake (Vieira and

Moran, 1998). Some workers (Abiola et al., 2008 and Oyerinde et al., 2008) reported

that in the starter phase of Anak broiler, daily feed intake increased with increase in

the size of eggs from where the chicks hatched while in the finisher phase there was

inverse relationship between feed intake and size of Table 5.9: Effect of broiler

breeder egg size on broiler feed intake at early

(30week) stage of production period (Means± SE)

Factors Egg size


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Weekly feed intake

(g)

First

Male 125.4±2.2 128.2±3.7 131.1±1.1 1.542 0.357

Female 126.7±3.2 126.3±3.7 124.4±0.9 1.476 0.828

Second

Male 493.2±2.4 495.8±3.1 500.9±2.7 1.727 0.250

http://www.researchgate.net/researcher/21171149_BO_Oyerinde/

http://www.researchgate.net/researcher/21171149_BO_Oyerinde/

168

Female 488.1±3.1 488.9±2.1 488.7±2.4 1.309 0.977

Third

Male 935.2b±1.5 939.2ab±3.2 944.8a±2.8 1.905 0.099

Female 930.7b±1.4 930.7b±1.4 938.4a±1.0 1.435 0.007

Fourth

Male 1660.9±2.8 1668.9±3.6 1672.2±3.5 2.376 0.122

Female 1641.2±1.1 1645.1±5.6 1650.9±2.9 2.332 0.257

Fifth

Male 2794.9±4.5 2824.6±33.2 2793.4±5.5 11.034 0.488

Female 2757.9±14.8 2735.1±5.2 2728.9±1.2 6.329 0.137

a-b Means with different letters in rows differ significantly (P≤ 0.05)

Table 5.10: Effect of broiler breeder egg size on broiler feed intake at mid

(45week) stage of production period (Means± SE)

Factors Egg size


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Weekly feed intake

(g)

First

Male 125.4±2.2 128.2±3.7 131.1±1.1 1.542 0.357

Female 126.7±3.2 126.3±3.7 124.3±0.9 1.475 0.828

Second

Male 493.2 ±2.4 495.8±3.1 498.4±1.8 1.445 0.392

Female 486.5±2.1 488.9±2.1 488.7±2.4 1.810 0.706

Third

169

Male 935.2±1.5 939.2±3.2 942.8±1.1 1.537 0.116

Female 929.1b±1.4 931.1ab±4.1 938.4a±1.0 1.923 0.090

Fourth

Male 1660.9±2.6 1689.9±3.6 1670.2±3.2 2.182 0.167

Female 1639.5±0.9 1640.8±2.2 1646.1±2.7 1.443 0.128

Fifth

Male 2782.2±2.9 2796.6±7.9 2797.7±7.3 4.077 0.244

Female 2743.1±4.4 2730.8±8.8 2728.9±1.2 3.628 0.241


Table 5.11: Effect of broiler breeder egg size on broiler feed intake at late (60week)

stage of production period (Means± SE)

Factors Egg size


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Weekly feed intake

(g)

First

Male 123.7±1.8 124.9±3.7 129.4±0.6 1.202 0.103

Female 126.7±3.2 126.3±3.7 124.4±0.9 1.475 0.828

Second

Male 493.2 ±2.4 495.8±3.1 500.4±2.7 1.7274 0.250

Female 488.1±3.1 488.9±2.1 488.7±2.4 1.3094 0.977

Third

Male 935.2a±1.5 939.2ab±3.2 944.8b±2.76 1.9047 0.099

Female 930.7±1.4 931.1±4.1 938.4±1.0 1.80237 0.133

Fourth

Male 1660.9±2.8 1668.9±3.6 1672.2±3.5 2.3767 0.122

170

Female 1641.2±0.9 1645.1±5.6 1649.0±4.7 2.418 0.482

Fifth

Male 2781.9±4.6 2790.6±5.8 2793.4±5.5 3.1915 0.351

Female 2741.2±2.2 2735.1±5.2 2733.0±3.6 2.297 0.361


eggs from where the chicks hatched. These results are harmony with present

experiment, during starter phase (at third week), feed intake significantly increased

with increase in the egg size at all stages of production period. In commercial

Leghorn breeder, during 2-4 weeks, chicks hatched from small-sized eggs consumed

less feed (p≤0.05) and egg size had non-significant (p≥0.05) subsequent effect on

pullet feed intake from 5 to 8 week (Leeson and Summers, 1989). They further

reported that pullets hatched from large-sized eggs, most often consumed more feed,

although this effect was significant (p≤0.05) only from 85 to 105 days of age and

overall (from 0 to 126 days) effect on feed intake was had nonsignificant (p≥0.05).

In contrast of the above findings, Ng’ambi et al. (2013) reported that

indigenous Venda chickens hatched from smaller eggs had higher (p≤0.05) feed

intakes than those hatched from heavier eggs. Similar results were obtained in

Japanese quail (Petek et al., 2003). This difference was due to breeds used in above

studies.

171

It is concluded that overall, egg size has no influence on feed intake of broiler

during growth phase except on 3rd week of growth period at all stages of production

period.

5.4.4 Effect of Breeder Age on Broiler Feed Intake

The influence of breeder age on feed intake in commercial Hubbard Classic

broiler breeder flock is shown in Table 5.12. Breeder age had non-significant

(p≥0.05) effect on broiler feed intake from first to fifth week of growth. These results

are agreed with findings of Onbaşılar et al. (2008), who reported that feed Table 5.12:

Effect of breeder age on broiler feed intake (Means± SE)

Factors Age (week)


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Weekly feed intake

(g)

First

Male 128.2±1.5 128.2±1.5 126.0±1.2 0.824 0.413

Female 125.8±1.5 125.8±1.5 125.8±1.5 0.819 1.000

Second

Male 496.5 ±1.7 495.8±1.4 496.4±1.7 0.911 0.939

Female 488.6±1.3 488.0±1.2 488.6±1.3 0.705 0.951

Third

Male 939.7±1.9 939.0±1.5 939.7±1.9 0.995 0.929

Female 933.3±1.4 932.8±1.9 933.4±1.8 0.962 0.949

Fourth

Male 1664.3±2.4 1666.7±2.2 1667.3±2.4 1.285 0.619

Female 1646.8±2.6 1642.8±2.5 1645.8±2.6 1.427 0.255

Fifth

Male 2804.3±11.0 2792.2±4.1 2788.6±3.2 4.1198 0.287

Female 2740.6±6.3 2734.2±3.6 2736.1±2.4 2.5246 0.499

a-c Means without letters in rows shows non-significant (P≥0.05) difference

172

consumption was not affected from Ross-308 broiler breeder age. The data showed

that feed intake from 1-3 weeks was found as 865, 943 and 910 g at 32, 48 and 61

weeks of age, respectively. Similarly, feed intake from 4-6 weeks was reported as

2864, 2942 and 2690 g at 32, 48 and 61 weeks of age, respectively. This study

revealed that feed intake regardless sex at 3 weeks was found on an average 936 g

at 30, 45 and 60 weeks of age. Similarly, feed intake at 5 weeks was found as 2772,

2763 and 2762 g at 30, 45 and 60 weeks of age, respectively. Leeson and Summers

(1989) reported same results in commercial Leghorn breeder that age of breeder had

no effect on feed intake of pullets. It is concluded that broiler breeder age is not

influenced on feed intake of broiler chick.

5.4.5 Effect of Hatching Egg Size on Broiler Feed Conversion Ratio

The effect of egg size on feed conversion ratio in broiler chicks derived from

broiler breeder flock at an early (30 week) stage of production period is shown in

Table 5.13. At this stage of production period, egg size had nonsignificant (p≥0.05)

effect on chick feed conversion ratio during growth period except in female during

2nd and 3rd week of growth. It was observed that female chick feed conversion ratio

was significantly (p≤0.05) improved with increasing the egg size at 2nd and 3rd weeks

of growth.

173


broiler breeder flock at mid (45 week) stage of production period is shown in Table

5.14. At this stage of production period, egg size had non-significant

(p≥0.05) effect on chick feed conversion ratio during growth period.


broiler breeder flock at late (60 week) stage of production period is shown in Table

5.15. At this stage of production period, egg size had non-significant

(p≥0.05) effect on chick feed conversion ratio during growth period except in female

during 2nd and 3rd week of growth. It was observed that female chick feed conversion

ratio was significantly (p≤0.05) improved with increasing the egg size at 2nd and 3rd

weeks of growth.

The results of current study are concurred with the findings of UlmerFranco

et al. (2010), who reported that egg size did not affect feed conversion ratio of

commercial Cobb -500 broiler breeder flock. The data indicated that early feed

conversion ratio (1 d to 21 d) was found as 1.41, 1.42 and 1.40 for small, medium

and large eggs, respectively. Similarly, late feed conversion ratio (22 d to 41 d) was

reported as 1.86, 1.84 and 1.86 for small, medium and large eggs, respectively. These

values are close to feed conversion ratio values in the present study at the same

growth period. In the previous study, Tufft and Jensen (1991) reported that as egg

weight of broiler breeder increased, body weight gain of the chicks also increased

but feed efficiency was not affected. The data showed that feed conversion ratio of

chicks at 0-3 weeks of growth was found as 0.64, 0.66 and 0.65 for small, medium

and large egg size groups, respectively derived from 37 weeks old hens. These values

of feed conversion ratio were better than values obtained in current experiment at 30

and 45 weeks old hens.

174

Both negative (Proudfoot et al., 1982) and positive correlations (Hearn, 1986)

of feed conversion with egg weight have been shown. Alabi et al. (2012) studied the

effect of egg weight on feed efficiency of Potchefstroom Koekoek chicks from 1 to

7 weeks of age and found that chickens hatched from large-sized eggs had better feed

conversion ratio than those hatched from small-sized eggs

175

broiler breeder egg size on broiler

Table 5.13: Effect of feed conversion ratio

at early (30 week) stage of production period (Means± SE)

Factors Egg size


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Weekly

Feed conversion

ratio

First

Male 0.888±0.0 0.875±0.0 0.878±0.0 0.0083 0.831

Female 0.904±0.0 0.903±0.0 0.901±0.0 0.0107 0.994

Second

Male 1.223±0.0 1.211±0.0 1.213±0.0 0.004 0.409

Female 1.242a±0.0 1.227ab±0.0 1.215b±0.0 0.005 0.033

Third

Male 1.361±0.0 1.357±0.0 1.354±0.0 0.002 0.314

Female 1.382a±0.0 1.371ab±0.0 1.365b±0.0 0.003 0.085

Fourth

Male 1.540±0.0 1.542±0.0 1.531±0.0 0.003 0.310

Female 1.565±0.0 1.553±0.0 1.5552±0.0 0.003 0.102

Fifth

Male 1.798±0.0 1.791±0.0 1.775±0.0 0.007 0.500

Female 1.808±0.0 1.808±0.0 1.796±0.0 0.004 0.541


176




Factors Egg size


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Weekly

Feed conversion

ratio

First

Male 0.863±0.0 0.853±0.0 0.848±0.0 0.008 0.741

Female 0.869±0.0 0.881±0.0 0.866±0.0 0.009 0.700

Second

Male 1.216±0.0 1.216±0.0 1.210±0.0 0.0033 0.412

Female 1.219±0.0 1.223±0.0 1.201±0.0 0.0048 0.272

Third

Male 1.362±0.0 1.364±0.0 1.366±0.0 0.0042 0.598

Female 1.373±1.4 1.372±1.4 1.370±0.0 1.368 0.807

Fourth

Male 1.533±0.0 1.542±0.0 1.548±0.0 0.0036 0.263

Female 1.550±0.0 1.551±0.0 1.552±0.0 0.0018 0.926

Fifth

Male 1.763±0.0 1.765±0.0 1.774±0.0 0.0027 0.211

Female 1.787±0.0 1.786±0.0 1.794±0.0 0.003 0.550


177




Factors Egg size


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Weekly

Feed conversion

ratio

First

Male 0.812±0.0 0.811±0.0 0.806±0.0 0.005 0.918

Female 0.838±0.0 0.805±0.0 0.791±0.0 0.0104 0.161

Second

Male 1.207±0.0 1.194±0.0 1.185±0.0 0.004 0.176

Female 1.223a±0.0 1.205b±0.0 1.188c±0.0 0.0054 0.002

Third

Male 1.362±0.0 1.357±0.0 1.355±0.0 0.0018 0.314

Female 1.382a±0.0 1.372b±0.0 1.371b±0.0 1.0023 0.055

Fourth

Male 1.533±0.0 1.530±0.0 1.532±0.0 0.0024 0.909

Female 1.565±0.0 1.558±0.0 1.562±0.0 0.0022 0.451

Fifth

Male 1.760±0.0 1.760±0.0 1.773±0.0 0.0027 0.211

Female 1.797±0.0 1.792±0.0 1.796±0.0 0.0030 0.826


178


179

although similar ratio was observed between large and medium sized eggs. Ng’ambi

et al. (2013) reported that chicks hatched from heavier eggs had better (lower)

(p≤0.05) feed conversion ratios. This is similar to the findings of Petek et al. (2003)

in quails. The above results are harmony with the present study; female chicks

hatched from large eggs had significant better FCR during second and third weeks

of growth when eggs derived at early and late stages of production cycle. However,

De Witt and Schwalbach (2004) found that FCR was better in chicks hatched from

medium sized eggs in New Hampshire and Rhode Island Red strains.

It is concluded that overall egg size had no effect on feed conversion ratio of

broiler in Hubbard broiler breeder rain.

5.4.6 Effect of Breeder Age on Broiler Feed Conversion Ratio

The influence of breeder age on feed conversion ratio in a commercial

Hubbard broiler breeder flock is shown in Table 5.16. Breeder age had significant

(p≤0.05) effect on broiler feed conversion ratio from 1-5 weeks of growth.

Generally, it was observed that feed conversion ratio was increased with advancing

age of breeder.

Peebles et al. (1999) reported that between 0 and 21 days, feed conversion

ratio of broilers from 51 week old breeders was significantly higher (1.605) than that

of broilers from 63 week old breeders (1.559), which, in turn, was significantly

higher than feed conversion ratio of those from 35 week old breeders (1.364).

Between 22 and 42 days, feed conversion ratio was significantly higher for broilers

from 35 week old breeders (3.258) compared to feed conversion ratio of broilers

from 51 and 63 week old breeders (2.757 and 2.722, respectively). The present

experiment data also showed in similar pattern that between 0-21 days, feed

180

Table 5.16: Effect of breeder age on broiler feed conversion ratio (Means± SE)

Factors Age (week)


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Weekly feed intake

(g)

First

Male 0.880a±0.0 0.870a±0.0 0.810b±0.0 0.00742 0.000

Female 0.903a±0.0 0.856b±0.0 0.811c±0.0 0.00928 0.000

Second

Male 1.216a±0.0 1.217a±0.0 1.195b±0.0 0.00313 0.002

Female 1.228a±0.0 1.212b±0.0 1.205b±0.0 0.00318 0.000

Third

Male 1.360a±0.0 1.364b±0.0 1.360a±0.0 0.0011 0.036

Female 1.371±0.0 1.375±0.0 1.373±0.0 0.00136 0.468

Fourth

Male 1.538ab±0.0 1.541a±0.0 1.532b±0.0 0.0018 0.096

Female 1.551ab±0.0 1.555a±0.0 1.562b±0.0 0.001741 0.014

Fifth

Male 1.789a±0.0 1.767b±0.0 1.767b±0.0 0.0034 0.010

Female 1.804a±0.0 1.789b±0.0 1.796ab±0.0 0.002314 0.035


181

conversion ratio of male broilers from 45 week old breeders was significantly higher

(1.364) than that of broilers from 60 week old breeders (1.360), which was at par

feed conversion ratio of those from 30 week old breeders (1.360). Between 22 and

35 days, feed conversion ratio was significantly higher for male broilers from 30

week old breeders (1.789) compared to feed conversion ratio of male broilers from

45 and 60 week old breeders (1.767 and 1.767, respectively).

In contrast of the present study, Onbaşılar et al. (2008) reported that feed

conversion ratio was not affected with age in broiler breeder. The data showed that

feed conversion ratio from 1-3 weeks was found as 1.25, 1.27and 1.26 at 32, 48 and

61 weeks of age, respectively. Similarly, feed conversion ratio from 4-6 weeks was

reported as 1.63, 1.68 and 1.71 at 32, 48 and 61 weeks of age, respectively. The

present experiment revealed that feed conversion ratio regardless sex at 3 weeks was

found on an average as 1.36 at 30, 45 and 60 weeks of age. Similarly, feed

conversion ratio at 5 weeks was found as 1.79, 1.78 and 1.78 at 30, 45 and 60

weeks of age, respectively. These values are found toward higher side than

above study. This showed Hubbard classic broiler breeder had poor feed conversion

ratio than Ross-308 broiler breeder. Similarly, Ulmer-Franco et al. (2010), who

reported that non-significant differences on early, late, or overall feed conversion

ratio between broilers hatched from 29 and 59 weeks old broiler breeder flocks. The

data indicated that early feed conversion ratio (1 d to 21 d) was found as 1.41, 1.41

at 29 and 59 week old breeder, respectively. Similarly, late feed conversions ratio

(22 d to 41 d) was reported as 1.84 and 1.86 at 29 and 59 week old breeder,

respectively.

182

Çabuk et al. (2006) reported that broilers originating from young Ross-308

broiler breeders had better FCR (1.54 and 1.78 at 21 and 42 d of growth period,

respectively) than those from old breeders (1.60 and 1.82 at 21 and 42 d of growth

period, respectively). However, this study showed that broiler hatched from 45 week

broiler breeder had better FCR (1.778) than broiler hatched from 30 and 60 weeks

older breeders (1.796 and 1.781respectively).

It is concluded that regardless sex chicks hatched from 45 week old breeder

had efficient FCR (1.778) than broiler chicks from 30 and 60 weeks older broiler

breeders (1.796 and 1.781respectively).

5.4.7 Effect of Breeder Hatching Egg Size on Mortality in Broiler The effect of

egg size on mortality in broiler chicks resulting from broiler breeder flock at an early

(30 week), mid (45week) and late (60 week) stage of production period are shown

in Tables 5.17, 5.18 and 5.19. Egg size had nonsignificant (p≥0.05) effect on

mortality percentage of chicks hatched from broiler breeder flock at different stages

of production cycle.

Results of current studied are agreed with some other studies. Singh et al.

(2003) and Ulmer-Franco et al. (2010) reported that mortality in broiler breeder

flock was not affected by egg size. Egbeyale et al. (2011) reported that regardless of

strain (Dominant Black and Yaffa Brown), the mortality throughout the rearing

period was non-significant (p≥0.05) though, the birds from small eggs had higher

numerical value of mortality (11.80%) followed by large egg size (4.85%) and

medium egg size (4.63%) groups at starter phase. Similar pattern was observed in

growing phase, high mortality in cockerels were found in small and large egg size

183

(2.38%) followed by medium egg size (1.67%) groups. Similar results were obtained

in Potchefstroom Koekoek chickens (1 and 7 weeks of age), the egg size did not

influence on mortality rate in these chickens (Alabi et al., 2012). The data

184

broiler breeder egg size on

Table 5.17: Effect of broiler mortality at early (30week)


Factors Egg size


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Weekly mortality

(%)

First

Male 2.22±2.2 2.22±2.2 2.22±2.2 1.112 1.000

Female 2.22±2.2 2.22±2.2 2.22±2.2 1.112 1.00

Second

Male 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Female 2.22±2.2 2.22±2.2 0.00±0.0 0.9804 0.630

Third

Male 2.22±2.2 0.00±0.0 0.00±0.0 0.7411 0.422

Female 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Fourth

Male 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Female 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Fifth

Male 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Female 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Cumulative 5 weeks

mortality (%)

Male 4.44±0.44 2.22±2.2 2.22±2.2 1.6163 0.851

Female 4.44±2.2 4.44±4.4 2.22±2.2 1.6144 0.850

Means without letters in rows shows non-significant difference (P≥0.05)

185


Table 5.18: Effect of broiler mortality at mid (45week)


Factors Egg size


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Weekly mortality

(%)

First

Male 2.22±2.2 2.22±2.2 2.22±2.2 1.112 1.00

Female 0.00±0.0 2.22±2.2 2.22±2.2 0.9804 0.630

Second

Male 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Female 2.22±2.2 0.00±0.0 0.00±0.0 0.7411 0.422

Third

Male 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Female 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Fourth

Male 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Female 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Fifth

Male 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Female 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Cumulative 5 weeks

mortality (%)

Male 2.22±2.2 2.22±2.2 2.22±2.2 1.112 1.00

1.00 Female 2.22±2.2 2.22±2.2 2.22±2.2 1.112


186


Table 5.19: Effect of broiler mortality at late (60week)


Factors Egg size


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Weekly mortality

(%)

First

Male 2.22±2.2 2.22±2.2 2.22±2.2 1.112 1.00

Female 0.00±0.0 2.22±2.2 2.22±2.2 0.9804 0.630

Second

Male 0.00±0.0 0.00±0.0 2.22±2.2 0.7411 0.422

Female 2.22±2.2 0.00±0.0 2.22±2.2 0.9804 0.630

Third

Male 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Female 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Fourth

Male 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Female 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Fifth

Male 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Female 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Cumulative 5 weeks

mortality (%)

Male 2.22±2.2 2.22±2.2 4.45±2.2 1.1718 0.729

Female 2.22±2.2 2.22±2.2 4.45±2.2 1.1718 0.729


187


188

showed that mortality rates were found as 10, 10 and 11% in chickens derived from

large, medium and small size eggs, respectively. In contrast to above studies,

Ng’ambi et al. (2013) reported that Venda chicks (1-7 weeks old) hatched from

heavier eggs had higher (p<0.05) mortality rates. The mortality rates were found as

2.5, 8.9 and 7.7% in chickens hatched from egg size 50-59 g, 60-69 g and >70 g,

respectively. These workers could not explain their results. It is concluded that

hatching egg size had no effect on broiler mortality.

5.4.8 Effect of Breeder Age on Mortality in Broiler

The influence of breeder age on mortality rate in commercial Hubbard

Classic broiler breeder flock is shown in Table 5.20. Breeder age had nonsignificant

(p≥0.05) effect on mortality rates in broilers reared from 1-5 weeks.

These findings are concurred with results of Ulmer-Franco (2010), who

reported that mortality percentages in broilers are independent on the age of parent

broiler breeders. Literature showed inconsistent results regarding effect of breeder

age on mortality percentage in broiler chicks. Peebles et al. (1999) found that broiler

mortality was reduced at 35 week (1.67 and 1.46 % for 0-21 and 22-45 d of growth,

respectively) and 51 week of breeder hen (3.37 and 1.72% for 0-21 and 2245 d of

growth, respectively) relative to that from 63 week old breeder hen (4.59 and 5.34%

for 0-21 and 22-45 d of growth, respectively). They explained that such higher

mortality rates in the broilers hatched from 63 old broiler breeders might be due to

inferior egg shell quality during late stage of production period. However, Mc

Naughton et al. (1978) reported a higher mortality rates in the chicks hatched from

29 week old breeder as compared to chicks from 58 week old breeders. Similarly,

Wyatt et al. (1985) studied significantly (p≤0.05) higher mortality percentages in

chicks hatched from 26 week old flock than the chicks from a 36 week old broiler

breeder. The most obvious characteristics of eggs from young broiler breeders are

189

low weight eggs with less yolk percentages and subsequent smaller day-old chicks.

Similarly, Singh et al. (2003) found that age of parent affected the mortality pattern.

The mortality was significant higher in followers whose parental age was less than

8 months as compared to those whose age more than 8 months. The results of above

studies showed that more mortality occurred in chicks derived from younger breeder

when compared to chicks from older broiler breeder. These findings are harmony

with the results of present study, numerically, over all maximum mortality was

occurred in chicks derived from young breeder hens as compared to older breeder

hens. It is concluded that breeder age had nonsignificant (p≥0.05) effect on mortality

in broiler chicks.

Table 5.20: Effect of breeder age on broiler mortality (Means± SE)

Factors Age (weeks)


No. of chicks 45♂+45♀ 45♂+45♀ 45♂+45♀ - -

Weekly mortality

(%)

First

190

Male 2.27±1.1 2.22±1.1 2.22±1.1 0.6166 1.000

Female 2.22±1.1 1.48±1.0 1.48±1.0 0.5732 0.841

Second

Male 0.00±0.0 0.00±0.0 0.74±0.7 0.2470 0.383

Female 1.48±1.0 0.74±0.7 1.48±1.0 0.5081 0.802

Third

Male 0.74±1.1 0.00±0.0 0.00±0.0 0.2470 0.383

Female 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Fourth

Male 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Female 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Fifth

Male 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Female 0.00±0.0 0.00±0.0 0.00±0.0 0.000 _

Cumulative 5 weeks

mortality (%)

Male 3.00±1.6 2.22±1.1 2.96±1.1 0.7345 0.901

Female 3.70±1.6 2.22±1.1 2.96±1.2 0.7409 0.732


Chapter 6

GENERAL DISCUSSION

Poultry industry, with its fast 8-10% growth rate annually, is the second

largest industry of Pakistan and playing a pivotal role in supplying animal protein

191

for the fast growing human population in Pakistan. Optimization of egg and meat

production can be achieved through updated hatchery and breeder farm management

regimens. The hatchery plays a central role in the breeder-hatcherybroiler

production chain. The successful hatchery operations are monitored by the good

hatchability percentage and number of saleable good quality healthy chicks. The

worldwide targeted average hatchability in broiler breeders during production period

is 85% but in Pakistan, it is observed approximately 79%. The 06% gap of low

hatchability between national and international industry is the huge loss of country

resources. This gap may extend in case of any problem at breeder or hatchery level.

This study was divided into four phases. The main objective of the first

phase of study was to evaluate the performance of broiler breeders in Pakistan and

to find out, how to optimize the production of broiler chicks so that the economic

output for the hatcheries and the breeder farmers could be improved. For this

purpose, a complete production data of 20 Hubbard Classic broiler breeder flocks

from 26 to 60 weeks of age were collected at random for the years 2005 to 2011

(seven years). Data were collected from the actual records saved at commercial

broiler breeder farms. The average percentages of egg production, hatching eggs,

egg weight and egg hatchability were found as 65.7%, 96.3%,

170

64.7g and 79.3%, respectively during production period. At 60 week of age,

average egg weight, hen housed eggs, hen housed hatching eggs and number of

chicks produced per hen housed were 69.8 g, 149.8, 145.1 and 119.10, respectively.

Feed consumptions per hatching egg and day old chicks were 395 and 486 g,

respectively. Male and female body weights at 60 week were observed as 4785 and

3929 g, respectively. In broiler breeder flocks, only 30% flocks were spiked.

192

Spiking of young males with aged males was started from 41 week and continued

to 55 week but spiking percentage varied in different weeks of flock age.

From this epidemiological study it was concluded that during production

period, good managed broiler breeder flocks showed gradually increased body

weights in male and female close to standard weights, resulted in good hatchability

and yielded maximum numbers of day-old chicks and consumed minimum feed for

one day-old chick. Under general management practices, commercial broiler

breeder flocks produced 19.9 less hen housed day-old chicks than standard (139).

For 12 million parent stocks in Pakistan, by achieving standard hen-housed day-old

chicks through good management practices we can save the wastage of 116056 ton

of broiler breeder feeds (saving of 4.12 million $) per annum for the better

economics of this developing country.

In second phase, main objective was to study the influence of egg size and

age on egg quality characteristics during early, mid and late stage of production

period in Hubbard Classic broiler breeder strain. In this experiment, a commercial

broiler breeder flock, Hubbard Classic strain (at 25 week of age) was selected for

study, located in Islamabad territory. A total of 2000 Hubbard Classic females and

180 males (male to female ratio 1:11) close to standard body weights were selected

and managed separately in the same poultry house. Male to Female ratio was kept

constant throughout production period. All the eggs laid during 4-8 hour of light

periods, from selected and separated broiler breeders, were collected from nests at

interval of one hour, at the early (30 week), middle (45 week) and late stage (60

week) of production period. The 930 eggs were selected from the hatching eggs at

the early, mid and late stage of production period and equally distributed into 3 egg

size categories (small, medium and large eggs). Ten eggs from each egg category

193

(having 310 hatching eggs) were analyzed for the following egg quality parameters

at the early, mid and late stage of production period.

The results showed that Egg size had non-significant (p≥0.05) effect on egg

quality parameters (shell weight, shell thickness, albumen weight, yolk weight, yolk

to albumen ratio, shape index and specific gravity) at early stage of production cycle.

In general, it was observed that shell weight, shape index and specific gravity

diminished with increasing the egg size at 45 weeks of breeder age. Maximum shell

weight percentage, shape index and specific gravity (p≤0.05) were evidenced in

small-sized (9.99%, 76.34 and 1.078, respectively), followed by medium-sized

(9.62%, 75.84 and 1.074, respectively) and large-sized (9.42%,

74.81 and 1.070, respectively) egg groups. No significant (p≥0.05) effect of egg size

on shell thickness, yolk weight (%), albumen weight (%) and yolk to albumen ratio

(%) was observed at mid stage of production period.

At late stage of production cycle (60 weeks), egg size had significant

(p≤0.05) effect on shell weight, shell thickness, shape index and specific gravity.

Overall, it was examined that shell weight, shell thickness, shape index and specific

gravity reduced with increasing the egg size. Maximum shell weight percentage,

shell thickness, shape index and specific gravity (p≤0.05) were observed in

smallsized (9.49%, 0.34mm, 74.64 and 1.068, respectively), followed by medium-

sized (9.05%, 0.33 mm, 73.81 and 1.065, respectively) and large-sized (8.82%,

0.32mm, 73.00 and 1.059, respectively) egg categories. Non-significant (p≥0.05)

effect of egg size on yolk weight (%), albumen weight (%) and yolk to albumin ratio

was observed at late stage of production period in broiler breeder.

The results showed that egg weight increased (p≤0.05) with advancing the

age as 56.45, 65.14 and 69.21 g at 30, 45 and 60 weeks of age, respectively.

Similarly, yolk weight (%) and yolk to albumen ratio were also improved (p≤0.05)

194

with advancing of age. However, shell thickness, albumen weight (%), shape index

and specific gravity were reduced (p≤0.05) with advancing of breeder age.

It is concluded that egg weight increased with progressing the production

cycle. The values of shell weight, shell thickness, shape index and specific gravity

of hatching eggs were decreased with increasing egg size. Percentages of yolk and

albumen weight were improved with increasing the egg size. The present research

proved that as the reproductive period of broiler breeders progressed, the weight of

their eggs increased. This fact was mainly due to the increasing yolk weight, because

its percentage in the egg mass increased with bird age, whereas the percentage of

the white decreased. The other factors like shell weight (%), shell thickness, shape

index and specific gravity of hatching eggs were proved to be significantly (p≤0.05)

lower with advancing of age.

In third phase, the objective of this phase was to study the effects of egg

size (small, medium and large) and flock age (30, 45 and 60 weeks) independent of

each other on hatching egg weight loss, fertility, hatchability traits, chick weight and

chick yield in a commercial Hubbard Classic broiler breeder flock. In this trial, 930

eggs were selected from the hatching eggs at the early (30 week), middle (45 week)

and late stage (60 week) of production period and were equally distributed into 3

egg size categories (small, medium and large). A total of 300 hatchable eggs from

each egg category (having 310 hatching eggs) were selected and shifted to

Rose hatchery, located near Khannapul Islamabad. These eggs were stored at 20oC

and 75% relative humidity for 3 days.

The results showed that at an early stage of production cycle, with the

increasing egg weight, egg weight loss percentage was decreased. Minimum egg

weight loss (p≤0.05) was observed in large-sized eggs at different incubation

periods. However, non-significant difference (p≥0.05) was found between small and

195

medium egg size groups. Egg weight loss determined during 18 days of incubation

in different egg-sized groups varied between 11.17 and 11.86% at 30 week of age.

Significant differences (p≤0.05) were found in egg weight loss of different egg size

groups at middle stage of production period. However, nonsignificant difference

(p≥0.05) was found between small and medium-sized eggs. Minimum egg weight

loss (p≤0.05) was recorded in large-sized eggs at different incubation periods. Egg

weight loss determined during 18 days of incubation in different egg size groups

varied between 10.92 and 11.32%. At late stage of production period, a similar trend

was found as data collected at early stage of production period. Egg weight loss

determined during incubation in different eggsized groups varied between 10.68 and

11.47% at 60 weeks of age. It is concluded that minimum egg weight loss was

occurred in large-sized eggs at different incubation periods. In addition, egg weight

loss percentage during incubation was significantly (p≤0.05) affected by breeder’s

age. Data showed that egg weight losses were decreased with advancing the age of

breeder hens. Thus, it is concluded that egg weight losses decreased with advancing

the age of breeder hens.

Egg size had significant (p≤0.05) effect on fertility and hatchability

parameters except pipped-not-hatched eggs and culled chicks at an early stage of

production period. Generally, it was observed that fertility and hatchability

percentage increased with increasing the egg size. Maximum fertility (p≤0.05) was

recorded in large-sized (95.67%), followed by medium-sized (92.67%) and

smallsized (90.33%) egg groups. Similarly, better hatchability percentage (out of set

eggs or fertile eggs) was found (p≤0.05) in large-sized (86.67 or 90.59%,

respectively), followed by medium-sized (82.33 or 88.81%, respectively) and small-

sized (70.67 or 78.11%, respectively) egg groups. However, non-significant

difference (p≥0.05) was found between medium and small-sized egg groups.

196

Maximum embryonic mortality (p≤0.05) during incubation was recorded in

smallsized eggs, followed by medium and large-sized egg groups. At early stage of

production period, maximum embryonic mortality (4.70%) was found in smallsized

egg group during 1st week of incubation. Higher percentage of infertile eggs

(p≤0.05) was also found in small-sized (9.67%), followed by medium-sized

(7.33%) and large-sized (4.33%) egg groups. No significant (p≥0.05) effect of egg

size was observed on pipped-not-hatched eggs and culled day-old chicks.

At mid stage of production cycle, maximum fertility (p≤0.05) was noticed in

small-sized eggs (96.65%), followed by medium (93.33%) and large-sized (90.13%)

egg groups. Similarly, maximum hatchability percentage (out of set eggs or fertile

eggs) was observed (p≤0.05) in small-sized (89.67 or 92.74%, respectively),

followed by medium (83.63 or 89.61%, respectively) and large-sized

(78.33 or 86.72%, respectively) egg groups. Maximum embryonic mortality

(p≤0.05) during incubation was recorded in large-sized egg group, followed by

medium and small-sized egg groups. At mid stage of production period, maximum

embryonic mortality (3.3%) was found in large-sized egg group during 1st week of

incubation. Higher percentage of infertile eggs (p≤0.05) was also found in largesized

(9.67%), followed by medium (6.67%) and small-sized (3.33%) egg groups.

No significant (p≥0.05) effect of egg size was observed on pipped-not-hatched

eggs. Maximum chicks (p≤0.05) were culled in large-sized egg group (2.0%).

At late stage of production period, maximum fertility (p≤0.05) was found in

small-sized eggs (91.0%), followed by medium (89.33%) and large-sized (85.67%)

egg groups. Similarly, better hatchability percentage (out of set eggs or fertile eggs)

was recorded (p≤0.05) in small-sized egg group (82.00 or 90.11%, respectively),

followed by medium (75.00 or 83.95%, respectively) and large-sized (64.33 or

75.08%, respectively) egg groups. Maximum embryonic mortality (p≤0.05) during

197

incubation was seen in large-sized egg group, followed by medium and small-sized

egg groups. At late stage of production period, maximum embryonic mortality

(5.67%) was observed in large-sized egg group during 1st week of incubation.

Higher percentage of infertile eggs (p≤0.05) was also found in large-sized eggs

(14.33%), followed by medium (11%) and small-sized (9.0%) egg groups. More

pipped-not-hatched eggs (p≤0.05) were observed in large-size egg group (4.33%).

In similar pattern, maximum chicks (p≤0.05) were also culled in large-sized egg

group (3.67%). The best combination of fertility and hatchability values were

recorded in medium-sized eggs (60-69g) and lower fertility was recorded in

largesize eggs (≥74.81g) at late stage of production cycle.

Age of the hens had a significant (p≤0.05) effect on fertility and hatchability

traits except embryonic mortality. Low fertility and hatchability (out of set eggs and

fertile eggs) were recorded (p≤ 0.05) in older hen at 60 week of age, however, the

effect of fertility and hatchability on ages (30 and 45 weeks) was nonsignificant

(p≥0.05). Age of hen was not influenced (p≥0.05) on embryonic mortality during

incubation. Numerically, more embryonic deaths occurred in older hens. More

(p≤0.05) infertile eggs and culled chicks were observed in older hens (60 week)

when compared with younger hens (30 and 45 weeks). However, older hen had

higher (p≤0.05) pipped-not-hatched eggs than younger hens.

Hatching egg size had a significant (p≤0.05) effect on chick weight at an

early stage of production period. It was observed that chick weight and chick length

were augmented (p≤ 0.05) with increasing the egg size. However, egg size was not

influenced (p≥0.05) on chick yield. At mid stage of production cycle, data

revealed that chick weight and chick length were amplified (p≤0.05) with increasing

the egg size. However, egg size was not influenced (p≥0.05) on chick yield.

Similarly, chick weight, chick yield and chick length were improved (p≤0.05) with

198

increasing the egg size at late stage of production period. Breeder age had a

significant (p≤0.05) effect on chick weight and chick length but insignificant

(p≥0.05) effect on chick yield. The results revealed that chick weight

and chick length were improved (p≤0.05) with advancing age of broiler breeder.

It was concluded that minimum egg weight loss was occurred in large-sized

egg group at different incubation periods. Egg weight losses were decreased with

advancing the age of breeder hens. For attaining better fertility and hatchability traits

in broiler breeder flock, regardless the age, medium egg weight (60-69g) should be

selected for incubation. Fertility and hatchability of the flock were reduced with

advancing the age of breeder hen. However, embryonic mortality, infertile eggs,

pipped-not-hatched eggs and culled chicks (not-saleable chicks) were increased with

advancing the age of breeder hen. Maximum chick weight was attained from large

egg size of breeder hen. Egg size (51 to 68.85g) had no influence on chick yield.

However, chick yield were improved with extra-large egg size (>70 g) of breeder

hen. Chick weight and chick length were improved with advancing of the age of

breeder hen.

In fourth phase, the main objective was to determine the effect of egg size

and age on post-hatching performance of Hubbard broiler chicks. At each stage of

production period (30, 45 and 60 week), 90 day-old chicks (45 males and 45

females) from each egg category (small, medium and large size) were selected

entirely at random from Rose hatchery. These 45 male and 45 female day-old chicks

from each egg size category were replicated thrice each having 15 day-old chicks

and shifted to a commercial semi-controlled shed located at Tumair village, in

Islamabad territory. These replicated day-old chicks were allotted randomly into 18

experimental units of shed. The birds were provided with commercial broiler starter

199

diet (0-10 days), broiler grower diet (11-25 days) and boiler finisher diet (from 26

to 35 days of age).

The results showed that chick weight at day-old, second and third weeks of

growth was significantly (p≤0.05) increased with increasing the egg size at an early

stage of production cycle. However, non-significant difference (p≥0.05) was found

in chick weight of different egg-sized groups at first, fourth and fifth weeks of

growth. Generally, it was noticed that chick weight increased with increasing the

egg size but the effect of egg size on chick weight becomes insignificant (p≥0.05)

from 4th week of age. At mid of production cycle, egg size had also significant

(p≤0.05) effect on female weights at second and third weeks of growth. It was

recorded that chick weight at day-old and female chick weight at second and third

weeks of growth were significantly (p≤0.05) increased with increasing the egg size.

Generally, it was examined that chick weight increased with increasing the egg size

but the effect of egg size on chick weight becomes insignificant (p≥0.05) from 4th

week of age. At late stage of production period, egg size had also significant

(p≤0.05) effect on chick weights at first (except on female weight), second and third

weeks of growth period. It was found that chick weight at day-old and at first

(except female weight), second and third weeks of growth were significantly

(p≤0.05) increased with increasing the egg size. Generally, it was observed that

chick weight increased with increasing the egg size but the effect of egg size on

chick weight becomes insignificant (p≥0.05) from 4th week of age. However, chicks

hatched from the medium-sized eggs (60-65g) gained numerically higher weight at

5 week of age. The results revealed that breeder age had a significant (p≤0.05) effect

on broiler growth from day-old to second week of growth. The results revealed that

chick growth was improved (p≤0.05) with advancing age of broiler breeder from 1d

200

to 14d. However, age had non-significant (p≥0.05) influenced on chick growth from

third to fifth weeks of growing period.

At an early stage of production period, egg size had non-significant

(p≥0.05) effect on chick feed intake during growth period except 3rd week of growth.

It was observed that chick feed intake was significantly (p≤0.05) increased with

increasing the egg size at 3rd weeks of growth. At mid stage of production period,

egg size had non-significant (p≥0.05) effect on chick feed intake during growth

period except in females at 3rd week of growth. It was found that female chick feed

intake was significantly (p≤0.05) increased with increasing the egg size at 3 rd weeks

of growth. At late stage of production period, egg size had also nonsignificant

(p≥0.05) effect on chick feed intake during growth period except in males at 3 rd week

of growth. It was observed that male chick feed intake was significantly (p≤0.05)

increased with increasing the egg size at 3rd weeks of growth.

Breeder age had no significant (p≥0.05) effect on broiler feed intake from first to

fifth week of growth.

Egg size had non-significant (p≥0.05) effect on chick feed conversion ratio

during growth period except in female during 2nd and 3rd week of growth at an early

production cycle. It was observed that female chick feed conversion ratio was

significantly (p≤0.05) improved with increasing the egg size at 2nd and 3rd weeks of

growth. At mid stage of production period, egg size had non-significant (p≥0.05)

effect on chick feed conversion ratio during growth period. At late stage of

production period, egg size had non-significant (p≥0.05) effect on chick feed

conversion ratio during growth period except in female during 2nd and 3rd week of

growth. It was observed that female chick feed conversion ratio was significantly

(p≤0.05) improved with increasing the egg size at 2nd and 3rd weeks of growth.

201

Breeder age had significant (p≤0.05) effect on broiler feed conversion ratio from 15

weeks of growth. It was concluded that regardless sex, chicks hatched from 45 week

old breeder had efficient FCR (1.778) than broiler chicks from 30 and 60 weeks

older broiler breeders (1.796 and 1.781respectively).

Egg size had non-significant (p≥0.05) effect on mortality of chicks hatched

from broiler breeder flock at different stages of production cycle. Similarly, breeder

age had insignificant (p≥0.05) effect on mortality in broilers, reared from 1-5 weeks.

Generally, it was concluded that broiler weight increased with increasing the

egg size. Regardless of stage of production period, the growth of chicks in the first

three weeks was influenced by egg size but by fourth week, this effect disappeared.

It was observed that chick growth was improved with advancing age of broiler

breeder from 1d to 14d. However, age had no (p≥0.05) influence on chick growth

from third to fifth weeks of growing period. Overall, egg size has no influence on

feed intake during growth phase except starter phase on 3rd week of growth at all

stages of production period. Breeder age is not influenced on chick feed intake. Egg

size had no effect on feed conversion ratio of broiler chicks obtained from Hubbard

broiler breeder flocks. At 5 week of age, efficient FCR was recorded in the chicks

hatched from breeder at mid stage (45 week) of production cycle than from younger

(30 week) or older (60 week) breeders. Breeder egg size and age had non-significant

(p≥0.05) effect on mortality in broiler chicks.

SUMMARY

This study was divided into four phases. The main objective of the first

phase of study was to evaluate the performance of broiler breeders. For this

202

purpose, a complete production data of 20 Hubbard Classic broiler breeder flocks

from 26 to 60 weeks of age were collected at random for the years 2005 to 2011

(seven years). The average percentages of egg production, hatching eggs, egg

weight and egg hatchability was found as 65.7%, 96.3%, 64.7g and 79.3%,

respectively during production period. At 60 week of age, average egg weight, hen

housed eggs, hen housed hatching eggs and numbers of chicks produced per hen

housed were observed as 69.8 g, 149.8, 145.1 and 119.10, respectively. Feed

consumptions per hatching egg and day-old chick were 395 and 486 g, respectively.

Male and female body weights at 60 week were observed as 4785 and 3929 g,

respectively. Only 30% flocks were spiked during production period. Spiking of

young males with aged males was started from 41 week and continued to 55 week

of age. The average production performance differed significantly (p≤0.05) with

strain standards and most of production parameters were observed below the

standards. Generally, it was observed that poultry breeders who, followed poor

management practices, resulted in low numbers (119.1) of day-old chicks per hen

house than standard (139).

In second phase, main objective was to determine the effect of egg size and

age on egg quality traits during early (30wk), mid (45wk) and late (60wk) stages

of production period in broiler breeder. A commercial broiler breeder flock of

Hubbard Classic strain (25 week old) was selected for this experiment. A total of

2000 Hubbard Classic females and 180 males (male to female ratio 1:11) were

182

selected and reared in the poultry house. Male to female ratio was kept constant

throughout production period. During 4-8 hour of light periods, a total of 930

hatchable eggs were selected at the early, mid and late stage of production period

and equally distributed into 3 egg-sized categories (small, medium and large). Ten

203

eggs from each egg category (having 310 hatching eggs) were analyzed for the egg

quality parameters within 24 hours of laying.

The results showed that egg size had non-significant (p≥0.05) effect on all

egg quality parameters (shell weight, shell thickness, albumen weight, yolk weight,

yolk to albumen ratio, shape index and specific gravity) at early stage of production

period. At mid stage of production cycle, it was observed shell weight, shape index

and specific gravity diminished with increase of egg. Maximum (p≤0.05) shell

weight, shape index and specific gravity were evidenced in small-sized egg,

followed by medium and large-sized egg groups. There was no significant (p≥0.05)

effect of egg size on shell thickness, yolk weight percentage, albumen weight

percentage and yolk to albumen ratio. At late stage of production cycle, it was

examined that shell weight percentage, shell thickness, shape index and specific

gravity reduced with increase of egg size. Maximum (p≤0.05) shell weight

percentage, shell thickness, shape index and specific gravity were observed in small-

sized, followed by medium and large-sized egg categories. There was nonsignificant

(p≥0.05) effect of egg size on yolk weight percentage, albumen weight percentage

and yolk to albumin.

The results showed that egg weight increased (p≤0.05) with advancing the

age as 56.45, 65.14 and 69.21 g at 30, 45 and 60 weeks of age, respectively.

Similarly, yolk weight percentage and yolk to albumen ratio were also improved

(p≤0.05) with advancing of age. However, shell thickness, albumen weight

percentage, shape index and specific gravity were reduced (p≤0.05) with advancing

of breeder age.

In third phase, the objective was to evaluate the effects of egg size (small,

medium and large) and flock ages (30, 45 and 60 wks) on hatchability and chick

quality traits. A total of 300 hatchable eggs from each egg category selected at early,

204

mid and late stage of production period, were shifted to broiler hatchery and stored

at 20 oC and 75% relative humidity for 3 days prior to incubation.

The results showed that at an early stage of production cycle, with the

increasing egg weight, egg weight loss percentage was decreased. Minimum egg

weight loss (p≤0.05) was observed in large-sized eggs at different incubation

periods. However, non-significant difference (p≥0.05) was found between small and

medium egg-sized groups. Egg weight loss determined during incubation in

different egg-sized groups varied between 11.17 and 11.86%. Significant

differences (p≤0.05) were found in egg weight loss of different egg size groups at

mid stage of production period. However, non-significant difference (p≥0.05) was

found between small and medium-sized egg groups. Minimum egg weight loss

(p≤0.05) was recorded in large-sized eggs at different incubation periods. Egg

weight loss determined during incubation in different egg-sized groups varied

between 10.92 and 11.32%. At late stage of production period, a similar trend was

found as data collected at early stage of production period. Egg weight loss

determined during incubation in different egg-sized groups varied between 10.68

and 11.47%. It is concluded that minimum egg weight loss was occurred in

largesized eggs at different incubation periods. In addition, data also showed that

egg weight losses were decreased with advancing the age of breeder hens. Thus it is

concluded that egg weight losses decreased with advancing the age of breeder hens.

Egg size had significant (p≤0.05) effect on fertility and hatchability traits

except pipped-not-hatched eggs and culled chicks at early stage of production

period. Generally, it was observed that fertility and hatchability increased with

increasing of egg size. Maximum fertility and hatchability values (p≤0.05) were

recorded in large-sized eggs, followed by medium and small-sized egg groups.

205

However, non-significant difference (p≥0.05) was found between medium and

small-sized egg groups. Maximum embryonic deaths (p≤0.05) during incubation

were recorded in small-sized eggs, followed by medium and large-sized egg groups.

Maximum embryonic deaths were found in small-sized egg group during

1st week of incubation. Higher percentage of infertile eggs (p≤0.05) was also found

in small-sized eggs, followed by medium and large-sized egg groups. No significant

(p≥0.05) effect of egg size on pipped-not-hatched eggs and culled chicks was

observed.

At mid stage of production cycle, maximum fertility and hatchability values

(p≤0.05) were noticed in small-sized eggs, followed by medium and large-sized egg

groups. Maximum embryonic deaths (p≤0.05) during incubation were recorded in

large-sized egg group, followed by medium and small-sized egg groups. Maximum

embryonic deaths were found in large-sized egg group during 1st week of incubation.

Higher percentage of infertile eggs (p≤0.05) was also found in largesized, followed

by medium and small-sized egg groups. No significant (p≥0.05) effect of egg size

was observed on pipped-not-hatched eggs. Maximum (p≤0.05) numbers of day-old

chicks were culled in large-sized egg group.

At late stage of production period, maximum fertility and hatchability values

(p≤0.05) were observed in small-sized eggs, followed by medium and largesized egg

groups. Maximum embryonic deaths (p≤0.05) during incubation were seen in large-

sized egg group, followed by medium and small-sized egg groups. Maximum

embryonic deaths were observed in large-sized egg group during 1st week of

incubation. Higher percentage of infertile eggs (p≤0.05) was also found in large-

sized eggs, followed by medium and small-sized egg groups. More pippednot-

hatched eggs (p≤0.05) were observed in large-sized egg group. In similar pattern,

maximum numbers of day-old chicks (p≤0.05) were also culled in largesized egg

206

group. The best combination of fertility and hatchability values were recorded in

medium-sized (60-69g) eggs and lower fertility was recorded in largesized eggs

(≥74.81g) at late stage of production cycle.

Age of the hens had a significant (p≤0.05) effect on fertility and hatchability

traits except embryonic deaths. Low fertility and hatchability (out of set eggs and

fertile eggs) were recorded (p≤ 0.05) in older hen (60wk), however, the effect these

traits on the ages (30 and 45 weeks) was non-significant (p≥0.05).

More (p≤0.05) infertile eggs and culled chicks were observed in older hen (60wk)

when compared with younger hens (30 and 45wks). Similarly, older hen (60wk) had

higher (p≤0.05) pipped-not-hatched eggs when compared with younger hens (30 and

45wks) in Hubbard classic broiler breeder strain.

Hatching egg size had a significant (p≤0.05) effect on chick weight at early

and mid-stages of production period. It was observed that chick weight and chick

length were augmented (p≤ 0.05) with increase of egg size. However, egg size was

not influenced (p≥0.05) on chick yield. Chick weight, chick yield and chick length

were improved (p≤0.05) with increase of egg size at late stage of production period.

Broiler breeder age had a significant (p≤0.05) effect on chick weight and chick

length and non-significant (p≥0.05) influence on chick yield.

In fourth phase, the main objective was to determine the effect of broiler

breeder egg size and age on post-hatching performance of broiler chicks. A total of

90 day-old chicks (45 males and 45 females) from each egg-sized category (small,

medium and large eggs) were reared for 5 weeks at early, mid and late stage of

production period.

The results showed that chick weight at day-old, second and third weeks of

growth was significantly (p≤0.05) increased with increasing of egg size at an early

stage of production cycle. However, non-significant difference (p≥0.05) was found

207

in chick weight of different egg-sized groups at first, fourth and fifth weeks of

growth. Generally, it was noticed that chick weight increased with increasing the

egg size but the effect of egg size on chick weight becomes insignificant (p≥0.05)

from 4th week of age. At mid of production cycle, egg size had also significant

(p≤0.05) effect on female weights at second and third weeks of growth. It was

recorded that chick weight at day-old and female chick weight at second and third

weeks of growth were significantly (p≤0.05) increased with increase of egg size.

Generally, it was examined that chick weight increased with increasing the egg size

but the effect of egg size on chick weight becomes insignificant (p≥0.05) from 4 th

week of age. At late stage of production period, egg size had significant (p≤0.05)

effect on chick weights at first (except on female weight), second and third weeks

of growth period. It was found that chick weight at day-old and at first (except

female weight), second and third weeks of growth were significantly (p≤0.05)

increased with increasing the egg size. Generally, it was observed that chick weight

increased with increasing the egg size but the effect of egg size on chick weight

becomes insignificant (p≥0.05) from 4th week of age. However, chicks hatched from

the medium-sized eggs (60-65g) gained numerically higher weight at 5 week of age.

The results revealed that breeder age had a significant (p≤0.05) effect on broiler

growth from day-old to second week of growth. The chick growth was improved

(p≤0.05) with advancing age of broiler breeder from 1 to 14 days. However, the

influence of age on chick growth from third to fifth weeks of growing period was

non-significant (p≥0.05).

At an early stage of production period, egg size had non-significant (p≥0.05)

effect on chick feed intake during growth period except 3rd week of growth. It was

observed that chick feed intake was significantly (p≤0.05) increased with increasing

the egg size at 3rd weeks of growth. At mid stage of production period, egg size had

208

non-significant (p≥0.05) effect on chick feed intake during growth period except in

females at 3rd week of growth. It was found that female chick feed intake was

significantly (p≤0.05) increased with increasing the egg size at 3rd weeks of growth.

At late stage of production period, egg size had nonsignificant (p≥0.05) effect on

chick feed intake during growth period except in males at 3 rd week of growth. It was

observed that male chick feed intake was significantly (p≤0.05) increased with

increasing the egg size at 3rd weeks of growth.

Breeder age had non-significant (p≥0.05) effect on broiler feed intake from first to

fifth week of growth.

Egg size had non-significant (p≥0.05) effect on broiler FCR during growth

period except female FCR during 2nd and 3rd week at early stage of production cycle.

It was observed that female chick FCR was significantly (p≤0.05) improved with

increasing the egg size at 2nd and 3rdweeks of growth. At mid stage of production

period, egg size had non-significant (p≥0.05) effect on broiler FCR during growth

period. At late stage of production period, egg size had nonsignificant (p≥0.05)

effect on broiler FCR during growth period except female FCR during 2 nd and 3rd

week of growth. It was observed that female chick FCR was significantly (p≤0.05)

improved with increasing the egg size at 2nd and 3rd weeks of growth. Breeder age

had significant (p≤0.05) effect on broiler FCR from 1-5 weeks of growth. . Broiler

chicks (regardless sex) hatched from 45 week old breeder had efficient FCR at 5 th

week than broiler chicks from younger (30wk) or older (60wk) broiler breeders. Egg

size had non-significant (p≥0.05) effect on mortality of broiler chicks hatched from

broiler breeder flock at different stages of production cycle. Similarly, breeder age

had insignificant (p≥0.05) effect on mortality in broilers, reared from 1 to 5 weeks.

209

CONCLUSION

As per epidemiological survey of 20 Hubbard Classic broiler breeder flocks,

it was observed that all production parameters were found below the strain standard

performance. Generally, farmers who followed poor management practices in

commercial broiler breeder flocks resulted in low numbers of day-old chicks per hen

house than strain standard. Egg size and age of broiler breeder influenced the egg

quality characteristics (shell weight percentage, shell thickness, albumen weight

percentage, and yolk to albumen ratio, shape index and specific gravity), egg weight

loss during incubation, egg hatchability traits and chick quality parameters. Growth

and feed intake of post-hatched broiler chicks in the first three weeks were

influenced by egg size and breeder age but by fourth week, this effect disappeared.

Chicks hatched from 45 week old breeder had efficient FCR than broiler chicks from

younger (30wk) or older (60wk) broiler breeders at 5 week of age. Egg size and

breeder age had no effect on mortality of broiler chicks.

210

190

Documents

ECONOMIC EVALUATION OF HATCHABILITY AND EFFECT OF …prr.hec.gov.pk/jspui/bitstream/123456789/7623/1/Javed iqbal Poultry... full pdf.pdfDay-old Chick 2.4.6 Spiking 2.4.7 Comparison