Effects of intermittent lighting on sleep and activity in the domestic hen

Abstract

This experiment deals with the effects of two different light-dark regimes on general activity, behavioural patterns and sleep in domestic hens ( Gallus domesticus). The light-dark schemes were composed of a traditional 14 h light-10h dark period and the Biomittent Lighting Program (BMLP), which consists of only 15 min light during every hour of the traditional 14 h photoperiod. Although it was found that hens are more active during the day than during the night, they were much less active under the BMLP-regime compared to the traditional regime. More specifically, there is considerable lowering of their activities during the dark portions of the day; behavioural observations revealed that they spend these periods not with resting behaviour, but with passive wakefulness. They more or less concentrate their daily activities during the 15-min light periods. Under the night period of the BMLP-regime, hens appeared to be more restless. Sleep recordings showed that sleep tended to decrease in favour of more drowsiness. It was concluded that circadian rhythmicity of the hens is maintained under both lighting schemes, although the BMLP-regime imposes more passive wakefulness during the day and slightly more activity during the night.