Food availability and the feeding and drinking behaviour of broiler chickens grown commercially.

1. Field observations were made on the effect of food depth in pans on the feeding and drinking behaviour of commercially grown broiler chickens aged between 17 and 43 d. 2. The group of birds receiving less food in pans had longer visits to the pans, occupied their feeding space more completely, evicted each other more often from pans and were more 'competitive' and less 'relaxed' when feeding. 3. These observations provide data about the feeding and drinking behaviour of broiler chickens reared in commercial conditions and emphasise how environmental factors, particularly food management, can influence bird behaviour. 4. The potential for qualitative and quantitative changes of feeding behaviour to affect performance is also discussed.