The aim of the study was to investigate the effect of chicken genotype on hatching time of chickens and to test possible relationships between hatching time, chicken sex, chicken weight, storage of hatching eggs and their external characteristics. Hatching eggs from three Slovenian provenances of laying hens of the light type (Prelux-G, Prelux-Č and Prelux-R) were marked, weighed, their height and width and shell color measured when they were placed in the setter. After 18 days of incubation, the eggs were transferred from the setter trays to the individual compartments of the hatching trays and the hatching time of the chickens was monitored. Every 8 hours, the hatcher was opened, and hatched chickens were weighed and sexed. The lowest variability in hatching time was found in Prelux-G chickens and the highest in Prelux-R chickens. Prelux-Č chickens hatched earliest (506.92 ± 0.30 h), and there were no significant differences in hatching times between the other two provenances. More females hatched than males at the beginning of the hatching window up to and including 501 h, with a male:female ratio of 1:1.68 for Prelux-G and Prelux-Č and 1:1.88 for Prelux-R, so that the hatching window of females was also longer than that of males. Females hatched earlier from hatching eggs of Prelux-R and Prelux-Č stored for shorter periods than from hatching eggs stored for longer periods. Of the external characteristics of the eggs, only the width of the eggs was significantly correlated with hatching time in all three provenances. In Prelux-G and Prelux-Č there was a statistically significant positive correlation between egg weight and hatching time, and in Prelux-R such a correlation was found between shell color and hatching time. In none of the three provenances can the sex of the hatched chickens be predicted from the external characteristics of the eggs.
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