The influence of light intensity during early exposure to colours on the choice of nest colours by laying hens

When alternative husbandry systems to battery cages are used, a problem may arise whereby eggs are not laid in the nests provided. This leads not only to economic loss, but may also promote the outbreak of cannibalism. However., the choosing of a nest involves complex behavioural patterns and may be influenced, among other things, by exposure to a specific colour at an early age [Huber-Eicher, B., 2004. The effect of early colour preference and of a colour exposing procedure on the choice of nest colours in laying hens. Appl. Anim. Behav. Sci. 86, 63-76]. Chicks exposed to the colours blue, green and red, preferred yellow nests when in lay, whereas exposure to yellow resulted in an indifference towards the colour of nest. In the study reported here, we further investigated this effect of exposure to yellow. During the first 12 days of life, chicks were exposed to either red or yellow and to either a high or low light intensity (four treatment regimes in total). A hen's choice of nest colour was tested at the start of lay (weeks 20-23). We randomly selected 20 hens from each of the four treatment regimes. The 80 chosen hens were then tested in groups of four, each of the four hens coming from a different treatment regime. When given a choice of nests painted in the colours yellow, red, blue or green, hens exposed to red and to a high light intensity at an early age showed a significant preference for yellow nests. Hens exposed as chicks to red and a low light intensity, or to yellow and either high or low light intensity were indifferent towards nest colour. In conclusion, we demonstrate that the effect of early exposure to yellow on reducing the preference for yellow nests later on, is due to the colour yellow per se, and not the higher light intensity that goes with it. However, high light intensity in combination with red increases the preference for yellow nests. (c) 2006 Elsevier B.V. All rights reserved.