Effect of extended storage on egg quality, embryo mortality and hatchability in FUNAAB‐ɑ chickens was determined. Hatchable eggs (n = 288; weighing 53.2 ± 4.67 g) collected from a flock of FUNAAB‐ɑ layer breeder hens aged 32 weeks were stored in egg tray with broad end up under 16 ± 1.5°C for either 0, 4, 8, 12, 16 or 20 d. Before incubation, eight eggs from each group were evaluated for internal and external quality traits. Remaining eggs were set in an incubator and transferred into hatcher on embryonic day 18. Data collected were subjected to one‐way analysis of variance. Egg weight loss (EWL; p < .001), surface area (p < .001), yolk diameter (p < .001), inner and outer blastoderm diameters (p < .05) and dead in germ (DIG; p < .001) increased with storage duration while yolk height (p < .001), yolk index (p < .001), albumen weight (p < .05), albumen height (p < .05), albumen index (p < .01), Haugh's unit (HU; p < .05), fertility (p < .001), hatchability of set (HATCHS; p < .001) and fertile eggs (p < .05) decreased. Weight losses of 0, 1.2, 2.2, 3.4, 4.6 and 6.1% were recorded in egg stored for 0, 4, 8, 12, 16 and 20 days respectively. Eggs stored beyond 8 days exhibited higher DIG and lower HATCHS. Shell percentage in 4 days storage (11.4%) was lower (p < .05) than in 16 days storage (13.4%). Shell thickness was similar in eggs stored for 0 to 12 days, but 8 days storage (0.60 mm) had thinner (p < .01) shell than day 16 (0.71 mm) and day 20 (0.73 mm) storage. Internal quality unit (IQU) was higher (p < .05) in fresh eggs (180.4) than in 12 days (167.8) and 20 days (167.8) stored eggs. Extended storage of FUNAAB‐ɑ eggs caused EWL, surface area shrinkage, lowered HU and IQU, loss of yolk and albumen quality, increased blastoderm diameters and DIG, and decreased egg fertility and HATCHS from day 8 forward. Storing FUNAAB‐ɑ eggs beyond 8 days reduced quality parameters; therefore, other mitigating factors are recommended when storing beyond 8 days.

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Adaptation of Nigerian indigenous chickens (NIC), FUNAAB‐α (F‐α) and Transylvanian naked neck chickens (TNN) raised during hot‐dry season under humid tropical environment was compared during a 4‐week period. A well‐adapted NIC (n = 12; 6 males and 6 females), a newly developed F‐α (n = 12; 6 male and 6 females) and a newly introduced TNN (n = 12; 6 male and 6 females) chickens aged 36 weeks were used for this experiment. Heart rate (HR), respiratory rate (RR), rectal temperature (RT) and skin temperature on comb (COM), wattle (WAT), breast (BRE) and under wings (WIN) were monitored between 13.00 and 14.00h twice a week for four weeks. Wattle temperature (p = .017) and BRE (p = .000) differ significantly among the genotypes. Transylvanian naked neck chickens recorded higher WAT than NIC, though not different from F‐α. Nigerian indigenous chickens had lower BRE temperature than other two genotypes. Significantly higher WAT (p < .001) and WIN (p < .05) were recorded in cocks than in laying hens. In contrast, laying hens had significantly (p < .001) higher RR and HSI than cocks. There was interactive (p < .05) effect of sex and genotype on BRE. Nigerian indigenous cocks and hens exhibited lower BRE than others, except F‐α cock. There were positive significant correlations between WIN and WAT in the three genotypes. In NIC, COM had positive correlation with WAT (r = .532) and WIN (r = .696). Heart rate was positively correlated with WAT (r = .608) and WIN (r = .697) in F‐α, and WIN (r = .512) in TNN chickens. In conclusion, the three genotypes can adequately adapt to the prevailing conditions of humid tropics. Reduction of feather on the neck and breast and higher heat loss capacity in TNN chickens could help the birds adapt to hot‐humid environment. The two sexes could adapt to the tropical region. Cocks lose body heat predominantly via non‐evaporative means while hens employ evaporative heat loss mechanism.

The blastoderm, which represents the fertilized germinal disc, undergoes cellular events of division, differentiation and organization to achieve embryonic development in chickens. In this study, blastodermal cell counts and hatching performance of Marshall ® broiler breeders as influenced by flock age and egg storage were investigated. A total of 1,520 eggs from the flock ages, 43 weeks (younger) and 65 weeks (older), under similar management and nutritional regime were incubated after storage at 16°C with 75% relative humidity for duration of 0 (fresh eggs), 4, 7 and 10 days. Results show that total blastodermal cell counts (BCC) for both ages declined with increasing storage duration, with a sharp regression at 4d storage from younger breeders. Higher percentages of fertility and hatchability were recorded for younger breeders compared to older breeders. Percentage hatchability was statistically similar (p > .05) for both 43 weeks and 65 weeks old broiler breeders under 0, 4 and 7d storage except at 10d storage which was lower for older breeders. Chick lengths were longer with younger breeders whereas older breeders had heavier chick weights. Also, significant associations were found between BCC and fertility, hatchability of fertile eggs and chick weights, respectively, under different conditions. These results indicate that fresh eggs (0d) and short-term stored eggs (4-and 7 d) from 43 weeks old breeders had higher total blastodermal cell counts, fertility, hatchability and increased chick lengths compared to 65 week old breeders which produced heavier chicks. Therefore, egg storage longer than 7 days especially from older breeders resulted in modifications to the blastoderm which subsequently affected fertility, hatchability, embryo liveability and hatched chick quality. Also, detection of BCC in fertile eggs can serve as a predictive tool in fertility and hatchability evaluations. K E Y W O R D S blastoderm, chick quality, egg storage, flock age, hatchability, Marshall ® broiler breeder | 1749 UYANGA et Al. How to cite this article: Uyanga VA, Onagbesan OM, Abiona JA, Egbeyale LT, Oke OE, Akinjute OF. Blastodermal development, hatchability and chick quality of Marshall ® broiler breeders of different flock ages during egg storage.

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