Effect of day length and natural versus incandescent light on perching and the diurnal rhythm of feeding behaviour in layer chicks (Gallus g. domesticus)

Not much is known about the effect of light sources on behavioural development of laying hens. The effect of natural and artificial light, respectively, on feeding and perching of layers was studied. 126-day-old chicks were divided into 1) A8: 8h artificial light+16h darkness, 2) A16: 16h artificial light+8h darkness, 3) N8: 8h daylight+16h darkness. A8 and N8 birds did not differ in their feeding behaviour, whereas the mean proportion of A16 birds feeding was 0.056 lower than in A8 birds in daytime (P < 0.001) and 0.019 lower in nighttime (P < 0.0001). N8 birds tended to start nighttime perching earlier than A8 birds (hazard ratio=8.5; P=0.056). These results suggest that chicks can change their feeding behaviour depending on day length. Natural daylight was found to precipitate the onset of nighttime perching in the life of the pullet.