Anotace:
The objective of this study was to compare some internal and external quality parameters of eggs during laying period at 7, 8 and 13 months of hen´s age.Hens of genetic animal resources of the Oravka breed from NAFC-RIAP Nitra were included in experiment. In our experiment the average egg weight was significantly increased with the age of the laying hens (P<0.0001, P=0.0076). There were significant differences in egg length and egg width, but no significant differences in egg shape index. The thickness of eggshell was demonstrably thinner in all measured positions of the egg with increasing age of laying hens. The average eggshell thickness decreased from 429.30 ± 1.25 µm to 420.98 ± 1.30 µm (P<0.0001) during the laying The albumen weight during laying varied from 31.29±0.36 g to 33.22±0.35 g. Albumen height and Haugh Unit measure the viscosity of the thick albumen. The Haugh Unit in Oravka breed were lower in the oldest hens(69.17±1.36). All yolk characteristics increased with age. The yolk weight increased from 14.64±0.21 g at the age of 7 months to 19.67±0.27 g at the age of 13 months (P<0.0001).We found significant differences in yolk colour only between hens of 8 and 13 months age (P=0.0021).