The Relationship of Oviposition Time and Egg Characteristics to the Daily Light:Dark Cycle

Hourly oviposition (egg laying) time and egg weight were studied over 24 hr in first-cycle commercial hens at 33 and 76 wk of age to gain better insight into profitable egg gathering practices. Eggs from two flocks (60,000 birds each) of White Leghorn hybrids were sampled directly of the egg belts in adjacent, similar houses. Hourly plots of oviposition times indicated that 50% of a young flocks eggs are laid within 13 hr after the beginning of the dark cycle, while in older flocks oviposition is delayed another 30 to 60 min. Linear regression of daily egg weights showed that eggs are consistently heavier in the morning and decline 2 to 9 g/egg/day between 0500 and 1800 hr. Coupled with other knowledge, including the daily change in shell integrity, the findings herein have applications for the mechanical gathering of eggs in a commercial setting to minimize egg breakage and increase the number of gradable eggs.