Effects of Outdoor Access and Indoor Stocking Density on Behaviour and Stress in Broilers in the Subhumid Tropics

摘要

The stressors affecting chickens in farming systems differ from those confronting their wild ancestors; thus, the ability to cope with an outdoor environment may have been modified. There is a growing body of literature that recognises the importance of allowing chickens to express their natural behaviour by providing outdoor access. However, studies investigating the effects of offering outdoor access to housed meat chickens in the tropics are scarce. Therefore, the effects of allowing chickens outdoor access, with two indoor space allowances, on their growth, behaviour and responses to stress were assessed. Some blood parameters indicated that outdoor access reduced stress, but the behavioural effects of providing outdoor access depended on indoor stocking density. Birds at the high stocking density with outdoor access were found standing for longer periods of time and those at the high stocking density and no outdoor access were observed walking less and lying more than the other three groups. It is concluded that there were welfare benefits of outdoor access, principally in terms of increased activity, but slower growth resulted in lighter birds at the end of the study.