Effects of Flock age, Length of Storage Period and Frequency of Warming before and during Egg Storage on Hatchability of Layer Breeder Eggs

Abstract

The experiment was conducted to evaluate the effect of flock age, length of storage and warming time before and during storage on hatchability of layer breeder eggs. A total of 1620 clean free from abnormalities fertile eggs were randomly selected from 75, 80 and 85wks old layer breeder (540 / age), each group was divided into three treatments (180 each), each treatment was replicated three times (60/replicate) then warmed before storage for 0, 3 and 6 hrs at 37.5°C and 53% RH, each replicate was furthered subdivided into three subgroup (20/ each) and stored for 4, 9 and 14 days at 18°C and 75% RH. Thereafter, half of the stored eggs (810) were warmed daily during storage for 0, 1 and 2hrs at 37.5°C and 53% RH. All eggs were weighed before the commencement of the experiment and when transfer to the Hatcher for the calculation of egg weight loss. After 4, 9 and 14 days of storage eggs were set in a setter at 37.5°C and 53% RH. At day 18 of incubation, hatching eggs were candled and infertile eggs were removed and opened to determine macroscopically infertile or stage of embryonic mortality to calculate true fertility. After candling, hatching eggs with living embryos were transferred to the hatchery baskets and placed in Hatcher cabinets in which the temperature and relative humidity were adjusted at 36.6°C and 75% RH. At the end of hatching process, hatched chicks were counted and weighed, hatchability on total and on fertile were calculated, unhatched eggs and pipped chicks were removed and opened to determine the stages of embryonic mortality, egg weight loss and chick yield were calculated and classified as first or second grade chicks based on their external feature. The results revealed that egg weight loss and chick yield were significantly (P≤0.05) affected by warming time, breeders age and storage period. Warming eggs before storage for six hours then stored for fourteen days had higher egg weight loss 13.33% and 14.67% when the breeder age 80 or 85weeks old. On the other hand, total weight losses and chick yield were significantly better 11.05 % and 68.12% when the breeders at 75 wks-old. Warming eggs before storage for six hours resulted in a significantly (P≤0.05) reduced the percentages of early 12.72%, mid 3.08% and late dead 4.57% compared to nonwarmed eggs 26.05% ,4.07 and 8.40 or eggs warmed for three hours 18.27% 2.84% and 6.05% , Early. Eggs stored for 14 days had significantly (P≤0.05) higher early dead 27.53%, mid dead 3.95% and late dead 6.79% compared to those stored for 4 and 9 days( 11.48%, 2.84%, 6.17%) (18.03%, 3.21%, 6.05%) respectively. On the Other hand, early 15.80%, 18.27%, 22.96%, mid 2.71%, 3.08%, 4.20% and late 4.81%, 5.19%, 9.01% embryonic mortality increased when the breeder age increased. Hatchability on total and on fertile were significantly (P≤0.05) affected by warming time before storage ,higher hatchability were recorded when the eggs warmed for 6 hrs (47.16%) and stored for 4 days(47.07%), meanwhile, hatchability on total and on fertile were decreased when the breeder age and storage period increased(50.87%,68.87%)(40.25%,59.67%)(25.18%,41.07%)(47.04%,6 9.43%)(40.25%, 58.72%) and (29.01%, 41.46%) respectively. Warming eggs before storage for 6 hrs significantly (P≤0.05) increase the (%) of first grade chicks (95.88%) and decrease the second grade (4.12%) compared to those warmed for 0.0 (67.4%)(32.55%) or 3hrs (90.84%)(9.16%).On the other hand, first grade chicks (%) were decreased when the flock age and storage period increased 75 , 80 to 85 wks old (91.14%, 86.52%, 76.51%), 4 , 9 and 14 days (90.52%,90.21%,73.45%). Egg weight loss significantly increased when warming time during storage (13.9%, 14.73%, 15.51 %), flock age (12.1% 15.59, 16.51) and storage period (13.65, 14.28%, 16.27%) increased. The best chick yield (66.82% and ,%68.12( first grade chicks (95.10%))%91.33( )%90.72( , hatchability on total and on fertile (49.88% and 67.58%) were obtained when the eggs were warmed for 1 hr and the flock age was 75wks. In conclusion, pre-storage warming of breeder's eggs for 6 hours or daily warming during storage for 1hr at 37.5°C and 53% RH and store for 4 days at 18ºC and 75%RH can be used by the poultry industry as a tool to improve hatchability results of late breeder eggs.