Comparison of the Behaviour of Broiler Chickens in Indoor and Free-Range Environments

Abstract
The behaviour of broilers reared at pasture from 4 to 12 weeks of age on a low density diet supplied either indoors or outdoors, was compared with that of birds reared inside on deep litter. This single study found few differences in behaviour. Activity levels of birds outside were initially greater, but from six weeks of age lying increased to comparable levels in all groups. Surprisingly little use was made of the extra space and facilities such as perches at pasture. It is proposed that the main reason for this was leg weakness as 80 per cent of the birds had a detectable gait abnormality at seven weeks of age. There was no evidence of reduced motivation to extend the behavioural repertoire, as, for example, ground pecking remained at significantly higher levels in the outdoor groups because it could also be performed from a lying posture.