Morphological characteristics of hatching eggs and hatching dynamics in Prelux-Č and Prelux-G laying hybrids and their relationship with chick sex

This study examined the morphological characteristics of hatching eggs from two Slovenian layer hybrids, Prelux-Č and Prelux-G, and investigated their relationship with hatch window and chick sex. The results showed significant (p ≤ 0.05) genotype-specific differences in egg morphology, hatching time and chick weight at hatch. Compared to Prelux-G eggs, Prelux-Č eggs were significantly (p ≤ 0.05) narrower, lighter and had paler shell pigmentation. Chicks from Prelux-Č eggs hatched earlier and had a significantly (p ≤ 0.05) lower body weight than chicks from Prelux-G eggs. The hatch window of the Prelux-G hybrids was 56 hours, while that of the Prelux-Č hybrids was 64 hours. In the Prelux-Č hybrids, the pullets hatched earlier than the cockerels, while no significant sex-specific differences in hatching time were observed in the Prelux-G hybrids. The duration of egg storage prior to incubation also influenced hatch timing, with chicks from eggs stored for seven days hatching later than chicks from eggs stored for two days; however, this difference was only statistically significant (p ≤ 0.05) in the Prelux-Č. The statistical analysis showed no significant correlation (p > 0.05) between the external egg characteristics and the sex of the chicks, indicating the limited predictive value of egg morphology for sex determination.