Lighting for laying hens: the effect of environmental factors on bird behaviour

Abstract

The light rhythm, as well as the quality of the light source is important for the early development of the layer chicken. Lighting may influence the incidence of behavioural problems, e.g. cannibalism, and these problems decrease with appriopriate rearing. Furthermore, the early exposure to perches and light type may influence the feeding and perching behaviour as well as later preference for light type. The aims of the studies were to investigate the individual differences in perching, and if environmental enrichment enhances perching at an early age, which is protecting against behavioural problems. The effect of natural and artificial light, respectively, on perching and feeding behaviour of laying hens was studied, as well as the light type preference of the birds at 14 weeks. In a separate on-farm study the lighting environments in common types of Swedish henhouses were investigated, and the HATO® light equipment was tested according to the legal requirements regarding bird health and welfare. It was found that the early perching of the chicks were positively associated with time spent under the perches, but negatively associated with social interaction. No significant effect of enrichment was found on the latency to start perching, although birds given access to enrichment on the floor had a tendency to roost earlier. It was found that chicks may change their feeding behaviour depending on day length, and access to daylight had a tendency to promote perching early in life. The start of night-time roosting was related to early day-time perch use. Birds reared in incandescent light showed a preference for incandescent light, in contrast to birds reared in natural light. In farms with various lighting systems, no severe problems of bird health or behaviour were found, except feather pecking.