Effects of Hatching and Feeding Times and Hatchery Temperature on Body and Organs’ Weight of Post-hatched Chicks

BACKGROUND: In commercial hatcheries, chicks are deprived of feed and water for up to 72 h, which is a det-rimental effect on growth performance. OBJECTIVES: Two experiments were designed to investigate the effect of hatching parameters and feeding time on the body and organ weights of chickens. METHODS: In the first experiment, 300 of both early- and later-hatched broiler chicks received feed immedi-ately after hatching or 48 h later and were divided into four experimental groups. The body and internal organ weights of chicks were determined for up to seven days. In the second study, 370 embryos, which were incubated in a setter until the 18th day, were transferred to two hatchers, which differed their air and eggshell temperatures. Then, hatching and post-hatched parameters were followed. RESULTS: Comparing early-hatched chicks, later-hatched chicks had significantly greater weight (p <0.05) on day 3 and better yolk utilization and higher relative liver and intestine (p <0.01) weights on day 2. However, early-fed chicks indicated significantly higher body weight (p <0.0001) until day 7 and early yolk utilization and higher internal organ weights than later-fed chicks. In the second experiment, when the air temperature of hatcher A (control) was kept at 37.5ºC, its eggshell temperature was determined at 38.5ºC, while the eggshell temperature of hatcher B was optimized at 37.5ºC, and its air temperature showed 36.5ºC. Earlier hatchability was higher in the control hatcher (46.8%) than hatcher B (27.1%), but later hatchability was reversed. However, final hatchability was lower in hatcher B (96.6%) than the control hatcher (98.3%). CONCLUSIONS: Later-hatched and early-fed chicks showed greater body and internal organ weights, indicating better maturation of these chicks. The results of the second study indicated that the hatching window could be shorter and also shifted to the end of the incubation time by reducing the egg temperature.