External and internal quality of eggs produced from aged hens.

An experiment was conducted to evaluate the quality of eggs produced from two genotypes aged hens, in specific points in molting period. In this study quality of eggs produced from ISA brown 88 weeks aged hens was compared with eggs produced from Hisex Brown 91 weeks aged hens. The values of external quality characteristics significantly decreased during the stress period in egg weight for 8.6% (p0.05) and 14.16% (p0.01) and become a little higher in second laying cycle (p0.05). The same trend was found in shell weight which was decreased for 70.36% and 69.36% (p0.01) and slowly increased in the second laying cycle 1.00% and 1.08% (p0.05) in the first (ISA Brown) and second (Hisex Brown) group. Shell thickness was decreased during stress period for 62.38% and 62.32% (p0.01) and still lower in the second cycle for 13.86% and 13.30% (p0.01) in first and second group. Internal characteristics in yolk weight were changed for 14.58% (p0.01) and 1.15% in stress period equalized closely 4.81% and 2.31% which was insignificant (p0.05). The yolk colour significantly decreased during stress period (p0.01) and equalized during the second cycle (p0.05). The yolk index between different specific points of molting in first group was improved in the second egg laying cycle for 6.5% and 6.3% (p0.05), but in the second group there was not found difference between preparing and second laying period, but it was found significant difference between stress period and preparing and second laying period for 12.4% and 12.8% (p0.01). Albumen height and Haugh units did not changed their quality during the stress period (p0.05), but in second laying period it was improved for 10% and 11% (p0.01) in first (ISA Brown) and second (Hisex Brown) group.