Behaviour of the Broiler Chicken as Affected by the Form of Diet

Poultry feeds are produced mainly in three physical forms; mash, crumbles and pellets. Even though the merits and demerits of these physical forms in relation to poultry production, processing cost and environment are well documented, form of the diet on the behaviour of broilers is less studied. Behaviour is an important aspect in animal welfare and, both directly and indirectly affects the production parameters. A completely randomized experiment was conducted to investigate the effect of two forms of the diet (mash or crumble) on the behavior of broiler chicken reared on deep litter. Observers were assigned to monitor the behavior of birds for a total of 6 hours on two consecutive days. Time spent on 5 major activities (feeding, drinking, walking, standing and lying) and four combined activities (feather brushing, inter-bird interaction, wing flapping and litter eating) were recorded. The total time spent on combined activities was around 14 % of the total time (6 hrs). Birds fed on crumble diets spent significantly (P<0.05) more time on litter eating than these fed on mash form diet (7.96 % ± 0.94 Vs 6.45 % ± 2.10). Since litter is an important source of vitamin B, significance of increased litter eating behavior needs to be further studied. Major activities consumed almost 84 % of the time. The time spent on feeding and drinking were significantly (P<0.05) higher for mash form diet fed birds (11.21% ± 2.94 and 5.04 % ± 0.57, respectively) compared to crumble diets fed birds (5.97% ± 0.94 and 4.51 % ± 1.50, respectively). The time spent on walking and standing was also numerically higher when mash form diets were fed. Birds fed on crumble diets spent significantly longer time on lying than when mash form diets were fed. Irrespective of the form of diet, lying was the most prominent behavioral activity taking 62% and 70 % of the total time for mash and crumble diets, respectively. Increased time on activities such as feeding, drinking, walking and standing in mash-form-diet fed birds may reduce the net energy available to the birds and increase the heat stress. Therefore the behavior of birds fed on crumble diets seems to have some indirect benefits on the energy value of the diet. Reduced heat production may be beneficial, particularly in hot climates. However, restriction of the activities due to crumble diet needs to be studied in relation to poultry welfare.