Effects of the time to change from incubation to hatching temperature on the artificial incubation of red-legged partridge (Alectoris rufa) eggs

This study investigates, in red-legged partridge (Alectoris rufa), the effects of the time to change from incubation to hatching temperature on egg weight loss, hatchability, chick weight at hatch, incubation length, and development stage at embryonic mortality. Five batches of 80 eggs each were incubated at 37.8°C during the first 18, 19, 20, 21 or 22 d of incubation, and subsequently at 37.5°C until hatching. Hatchability, development stage at embryonic mortality and chick weight at hatch were not affected by the time of temperature change (p > 0.05). However, incubation length and egg weight loss after 21 d of incubation as representative of that of developed embryos were influenced by the incubation treatment (p < 0.001 and p < 0.05, respectively). Thus, eggs maintained at the incubation temperature of 37.8°C for 22 d not only hatched earlier (23.04 d) but also with lower dispersion than eggs from the other treatments. As hatching may start around day 22 of incubation, to improve hatching synchrony we could recommend to move A. rufa eggs from the incubator, set at 37.8°C, to the hatcher on the 21st d of incubation keeping the temperature unchanged, and reduce it to 37.5°C on the 22nd d. Nevertheless, further research should be carried out to study the effect of this temperature scheduling on chick growth and performance.