Production responses of laying hens to 28 h bright:dim light cycles using different light intensity ratios and a 24 h...

Seven hundred and twenty laying hens housed in 8 environmentally-controlled rooms were changed from a 24 h light:dark cycle to a 28 h ahemeral bright:dim cycle. The ahemeral cycles consisted of periods of bright and dim light in ratios of intensity: 5:1, 10:1 and 30:1. The last regimen was applied either at a constant 21 degrees C or with a 24 h alternating temperature varying between 21 and 31 degrees C. Eggs were collected hourly from each bird for 5 d immediately before the introduction of ahemeral cycles and then over the same period 2 weeks after introduction. The interval between successive eggs within sequences lengthened with increasing bright:dim ratios. The increase in egg weight and decrease in deformation score were not significant. Total egg mass output was not altered. The cycling temperature regimen did not alter the entrainment of the birds, although intra-sequence interval decreased. The decrease in egg weight and increase in deformation score were not significant.