RESUMEN
An effect of modification of storage conditions of the eggs of broiler breeder flocks at the age of 49-, 52- and 70-, 73-wks of life on an early embryonic development, hatching time and synchronization, hatchability rates, chicks quality and broiler growth was investigated. The eggs were divided into 4 experimental groups: COI = eggs storage 5 d, at turning every 12 h; NSP = eggs storage 12 d, at turning every 12 h; SPIDES = were treated with 4 h pre-incubation at 30°C and 50-55% air humidity, delivered at 5 and 10 d over of 12 d of storage, and turning every 12 h; NCOI = eggs storage 12 d, no turning and no pre-incubation. Eggs from older hens were characterized by poorer hatchability and poorer chicks quality. The use of 2 × 4 h pre-incubation in 12 d of eggs storage could have an effect on the initial acceleration of embryonic development in eggs of young hens, contributing to the alignment of embryos development in eggs from young and older hens to 72 h of incubation. Pre-incubation had no effect on the length of incubation period, hatching window, but it increased the hatchability of the set and apparently fertilized eggs and decreased the number of eggs not hatched, and also improved chicks quality. Eggs turning by 90° every 12 h during the storage positively affected the embryonic development, shortening the incubation time and the quality of chicks, but had no effect on hatchability rates and body weight in 42 d of life. Based on the obtained results, it can be concluded that the applied modifications can be effective in counteracting the negative effects of storage of hatching eggs from both young and older birds.