Quality of eggs laid at different times of the day by hens with different egg production levels

The aim of the study was to assess the development of the quality of eggs laid at different times of the day by hens with low egg production (Green-legged Partridge strain Z-11) and higher egg production rates (Rhode Island White strain A-33). The research material consisted of eggs collected from these two breeds/strains of laying hens included in the conservation programme in Poland. During the 24–56 weeks of age, all eggs at 7:00, 10:00 and 13:00 h were collected every 4 weeks from each breed of hens from the same compartment and analysed for internal egg quality and egg shell quality. In addition, at 40 weeks of age for 3 days, 10 eggs each were collected at the aforementioned times of the day and sent to the Institute’s Central Laboratory for chemical analysis of their yolks. In the study conducted, statistically significant differences were found for most physical and chemical egg quality traits between eggs derived from Green-legged Partridge hens (strain Z-11), an old native breed with low egg production rates, and eggs obtained from Rhode Island White hens (strain A-33) with much higher egg production rates. For most egg quality traits, there was no clear relationship with oviposition time.