Effect of the Colour of Light on Growth Performance, Behaviour and Bone Parameters of Broiler Chicken

This study examined the effect of the colour of light on growth performance, feed and water intake, behaviour and latency to lie (LTL) in broiler chickens. Ninety six broiler (Hybro P.G. Plus) chicks were divided into two groups and reared in 12 cages that received either red or white colour light (20 lux) during night for 8 hrs per day from 14-36 d of age. Water and feed were provided ad libitum. Behaviour was recorded on the broad mutually exclusive categories, walking, standing, litter eating, drinking, eating, aggression, feather pecking, bird interaction, lying and dust bathing by adopting scan sampling method. Birds were weighed weekly. Daily feed intake and water intake were measured during day time and during the artificial lighting period. Though light colour did not affect the final body weight (BW), birds reared under red colour light tended (P=0.08) to have higher weight gain (1366 g) compared to those grown under white light (1305 g). Feed and water consumption patterns, feed conversion ratio (FCR) were not significantly affected by the colour of lighting. Irrespective of the light colour, the average feed and water intake of the birds were (P<0.05) higher during day time compared to those at night time. Broilers who received red colour lighting during night time had high LTL during day time. However, the overall LTL results showed that birds exposed to white light had significantly (P<0.005) higher LTL (3.13 min.) than those exposed to red light in the night (1.61 min.). Bone parameters were not affected by the colour of light. When the behavioural parameters were considered, drinking during night time was high under red light condition. A high tendency of lying down during day time was observed when birds were exposed to white light during night. Feather pecking and dust bathing behaviours during day time were high (P<0.05) among the birds that were exposed to red light during night. These results suggest that rearing broiler chicken in red or white colour lights at 20 lux intensity during night time in a hot, humid tropical environment has no effect on growth, performance but affects behaviour and LTL. INTRODUCTION Eyes are the main sense organs, and vision is one of the main senses that influence broilers. Light environments that restrict the efficacy of visual possessing may reduce welfare if important visual information is lost or corrupted by the environment. For example, birds Department of Animal Science, Faculty of Agriculture, University of Peradeniya, Peradeniya, Sri Lanka. Department of Animal Science, Faculty of Agriculture, University of Ruhuna, Mapalana, Sri Lanka.