TABLE OF CONTENTS
Title Page .. .. .. .. .. .. .. .. .. i
Certification .. .. .. .. .. .. .. .. ii
Dedication .. .. .. .. .. .. .. .. .. iii
Acknowledgement .. .. .. .. .. .. .. iv
Table of contents .. .. .. .. .. .. .. v
List of Tables .. .. .. .. .. .. .. .. viii
List of figures .. .. .. .. .. .. .. .. ix
Abstract .. .. .. .. .. .. .. .. .. x
CHAPTER ONE
Introduction
- Background .. .. .. .. .. .. .. 1
- Statement of problem .. .. .. .. .. 3
- Objectives of study .. .. .. .. .. 3
- Justification of study .. .. .. .. .. 4
CHAPTER TWO
Literature Review
2.1 Classification of chickens .. .. .. .. .. 5
2.2 Exotic breed of laying birds .. .. .. .. .. 5
2.3 The reproductive system of the laying hen .. .. 6
2.3.1 The Ovary .. .. .. .. .. .. .. .. 7
2.3.2 The Oviduct .. .. .. .. .. .. .. 8
2.3.3 Ovulation .. .. .. .. .. .. .. .. 9
2.3.4 Egg formation .. .. .. .. .. .. .. 12
2.4 Oviposition .. .. .. .. .. .. .. 12
2.4.1 Sequential laying .. .. .. .. .. .. 13
2.4.2 Sequence/Clutch length .. .. .. .. .. .. 15
2.4.3 Pause days .. .. .. .. .. .. .. 15
2.4.4 Ovpiosition time .. .. .. .. .. .. .. 16
2.4.5 Time interval between successive eggs and lag .. .. 16
2.4.6 Total egg production .. .. .. .. .. .. 17
2.4.7 Rate/Intensity of lay .. .. .. .. .. .. 17
2.5 Egg quality .. .. .. .. .. .. .. 18
2.5.1 Egg weight .. .. .. .. .. .. .. 19
2.6 Physical characteristics of hens .. .. .. .. 19
2.7 Climatic condition .. .. .. .. .. .. 21
CHAPTER THREE
Materials and Methods
- Location and duration of study .. .. .. .. .. 23
- Experimental birds .. .. .. .. .. .. 25
- Management of hens .. .. .. .. .. .. 25
- Parameters measured .. .. .. .. .. 25
- Oviposition time .. .. .. .. .. .. 25
- Total egg production .. .. .. .. 25
- Clucth/sequence length .. .. .. .. .. 26
- Pause days .. .. .. .. .. .. .. 26
- Egg weight .. .. .. .. .. .. .. 26
- Egg quality .. .. .. .. .. .. .. 26
- Average daily feed intake .. .. .. 27
- Percentage egg production .. .. .. 27
- Physical characteristics .. .. .. .. .. .. 27
- Temperature .. .. .. .. .. .. .. .. 28
- Experimental design .. .. .. .. .. .. ..
- Statistical analysis .. .. .. .. .. .. .. 28
CHAPTER FOUR
Results and discussion
4.1 Results
4.1.1 Egg laying characteristics of Shaver brown hens .. 29
4.1.1.1 Oviposition time .. .. .. .. .. .. .. 29
4.1.1.2 Total egg production .. .. .. .. .. .. 31
4.1.1.3 Clutch length .. .. .. .. .. .. .. 31
4.1.1.4 Pause days .. .. .. .. .. .. .. .. 37
4.1.1.5 Egg weight .. .. .. .. .. .. .. .. 37
4.1.1.6 Intensity/ Rate of lay .. .. .. .. .. .. 37
4.1.1.7 Hen housed egg production (HHEP) .. .. .. .. 39
4.1.1.8 Hen day egg production (HDEP) .. .. .. .. 39
4.1.2 Egg laying characteristics of Nera black hens .. .. 41
4.1.2.1 Oviposition time .. .. .. .. .. .. .. 41
4.1.2.2 Total egg production .. .. .. .. .. .. 43
4.1.2.3 Clutch length .. .. .. .. .. .. .. 43
4.1.2.4 Pause days .. .. .. .. .. .. .. .. 50
4.1.2.5 Egg weight .. .. .. .. .. .. .. 50
4.1.2.6 Intensity/ Rate of lay .. .. .. .. .. 50
4.1.2.7 Hen housed egg production (HHEP) .. .. .. 51
4.1.2.8 Hen day egg production (HDEP) .. .. .. 51
4.1.3 Effect of temperature on performance of Shaver brown
and Nera black hens .. .. .. .. .. .. 55
4.1.4 Interaction of strain and temperature on Performance .. 57
4.1.5 Physical characteristics of hens .. .. .. .. 57
4.1.6 Comparison between strains for performance and egg
quality traits .. .. .. .. .. .. .. .. 58
- Discussion
4.2.1 Climatic data for Nsukka .. .. .. .. .. .. 60
4.2.2.1 Egg laying characteristics of Shaver brown
and Nera black hens .. .. .. .. .. 60
- Oviposition time .. .. .. .. .. .. .. 60
- Total egg production and other egg productionIndices .. 61
- Clutch length .. .. .. .. .. .. .. 61
- Pause days .. .. .. .. .. .. .. .. 62
- Egg weight .. .. .. .. .. .. .. .. 62
- Effect of temperature on performance of Shaver
brown and Nera black hens .. .. .. .. 63
- Interaction of strain and temperature on performance .. 65
- Physical characteristics .. .. .. .. .. .. 67
- Comparison between strains for performance and egg
quality traits.. .. .. .. .. .. .. .. 69
CHAPTER FIVE
Summary and conclusion .. .. .. .. .. .. 71
References .. .. .. .. .. .. .. .. .. 72
Appendices .. .. .. .. .. .. .. .. 81
LIST OF TABLES
Table 1: Times of egg laying in hens .. .. .. .. .. .. 14
Table 2: Mean weekly environmental temperatures and relative humidity during
the period of the study .. .. .. .. .. .. .. 24
Table 3: Frequency distribution of egg production of Shaver brown hens .. 30
Table 4: Frequency distribution of mean clutch length of Shaver brown hens 32
Table 5: Effect of egg position and clutch size on egg weight of Shaver brown hens 33
Table 6: Frequency distribution of pause days of Shaver brown hens 34
Table 7: Effect of oviposition interval on egg weight of Shaver brown hens.. 36
Table 8: Frequency distribution of egg laying of Shaver brown and Nera
black hens during the day .. .. .. .. .. .. 38
Table 9: Classification of experimental hens .. .. .. .. .. 40
Table 10: Frequency distribution of egg production of Nera black hens .. 42
Table 11: Frequency distribution of mean clutch length of Nera black hens .. 44
Table 12: Effect of egg position and clutch size on egg weight of Nera black hens 45
Table 13: Frequency distribution of pause days of Nera black hens .. .. 46
Table 14: Effect of oviposition interval on egg weight of Nera black hens .. 49
Table 15: Comparison between strains for performance and egg quality traits 52
Table 16: Effect of temperature on performance of Shaver brown hens .. 63
Table 17: Effect of temperature on performance of Nera black hens 54
Table 18: Effect of interaction of strain and temperature on performance 56
LIST OF FIGURES
Figure 1: Frequency distribution of egg laying of Shaver brown hens
at different oviposition intervals during the day .. .. 35
Figure 2: Frequency distribution of egg laying of Nera black hens
at different oviposition intervals during the day .. .. 47
Figure 3: Average weekly temperatures (Indoor and Outdoor) and relative
humidity of the study area .. .. .. .. .. 48
ABSTRACT
A total of one hundred and fifty Shaver brown and Nera black hens in their 14th week of lay were used in a study conducted to determine the laying and physical characteristics of Shaver brown and Nera black hens under humid tropical environment. Hens were housed individually in separate cages. The hens were supplied water ad libitum and fed layers mash containing 16.5% crude protein and 2650 kcal/kg of metabolizable energy for 10 weeks. The hens were also divided into three classes based on their laying performance as follows: good layers, intermediate layers and poor layers and their physical conditions appraised. Temperature readings were taken 3-hourly at time intervals of 0900h, 1200h, 1500h, and 1800h using a standard air thermometer and the mean daily temperatures noted. The climatic data taken during the period of the experiment showed that the study area had the natural day-length of 13 to 14 hours; mean maximum weekly indoor and outdoor temperatures of 27.90C to 29.20C and 26.80C to 30.50C, respectively; mean minimum weekly indoor and outdoor temperatures of 20.50C to 22.30C and 20.00C to 23.600C, respectively; relative humidity of 73.1% to 76.6% and mean total monthly rainfall of 781.33mm. Results showed that the peak of lay was between 0700h and 0800h and declined gradually throughout late afternoon hours until no egg was laid between 1700h and 1800h. For Shaver brown hens, about 86.24% and 13.76% of the eggs were laid in the morning and afternoon hours respectively, while 88.75% and 11.25% of the eggs were laid in the morning and afternoon hours respectively, for Nera black hens. Mean egg weight of 70.05g±1.07 and 70.10g±0.92 for eggs laid between 0600h and 0700h for Shaver brown and Nera black hens, respectively were the heaviest (P<0.05) of all the mean egg weights observed in all oviposition intervals. For Shaver brown hens, first eggs laid in a clutch were significantly greater (P<0.05) than subsequent eggs laid in a clutch, while the first eggs in a clutch for Nera black were greater than other eggs in the clutch, although the differences were not significant (P>0.05). Hens with the longest clutches and shortest number of pause days produced the greatest number of eggs. The total number of pause days observed were 1410 and 1329 for Shaver brown and Nera black hens, respectively. Observations made on physical characteristics of the hens revealed that good layers had smooth combs and wattles, moist and enlarged vents with flexible pubic bone, soft abdomen and worn out feathers. Intermediate layers had similar features with good layers except that the eye rings, beaks and shanks were slightly bleached. Poor layers had dry combs and wattles, tight and hard abdomen and closed pubic bones. The Effect of ambient temperature on performance parameters showed that for Shaver brown hens, hen day egg production, average daily feed intake, egg shell weight, egg shape index, albumin height, yolk height, yolk height and Haugh units were significantly reduced (P<0.05) with increasing temperatures. All performance parameters measured for Nera black hens were significantly reduced (P<0.05) with increasing temperatures. Likewise, there was significant interaction (P<0.05) of strain and temperature on average daily feed intake and yolk height. The results of the present study indicate that although heat stress had effect on performance, Shaver brown and Nera black hens are adapted to humid tropical environment and can lay 86.24% and 88.75% eggs, respectively in the morning hours, with overall production rate of 66.43% and 68.36% respectively, for Shaver brown and Nera black hens.
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
The growth in global demand for poultry products is tremendous as the market for these products is growing very fast. Poultry is probably the fastest route to achieve any appreciable improvement in the nutritional standard of the populace because of its short generation interval, quick turnover rate and relatively low capital investment (Smith, 2001; Ani and Okeke, 2011). Gueye (2000) asserted that 85% of rural households in Sub-Saharan Africa keep chickens or other types of poultry. Poultry are equally important to other smallholders in Asia, Latin America and other parts of the world (Mallia, 1999; FAO, 2003; Islam and Jabbar, 2005; Kyrsgarrd, 2007). Increased egg production is one sure way of achieving the target of providing quality animal protein at a minimum cost to the consumers (Oluyemi and Roberts, 2000). Advances in genetic selection make today’s commercial layers quite different from those of years ago. Body weight is less, age at housing is earlier, total egg number has increased, egg mass is greater and feed conversion has improved considerably (Miles and Jacob, 2000; Minivielle et al., 2006). Total egg production is affected both by the physical and laying characteristics of the hen. Laying characteristics of hens have been assessed by evaluating such indices as rate of lay, oviposition time, clutch/sequence length, number of pause days, lag time, hen housed egg production (HHEP), and hen day egg production (HDEP).
Physical characteristics of laying hens on the other hand, consist of those features that can be seen easily on their body such as condition of combs, wattles, eyes, beaks, pubic bones, abdomen and vent. They are used to determine whether a hen is laying or not (Gillespie, 1997; Reddy et al., 2004; Daghir, 2008; Ani and Nnamani, 2011).