Behavioural and physiological responses of laying hens to humans

Human interactions, particularly negative ones, affect the behaviour and physiology of laying hens, with possible implications for bird productivity and welfare. The present experiment investigated the effects of handling on the behaviour and plasma corticosterone concentrations of laying hens. A 2 × 2 × 3 factorial design was used to study the following three main effects: human contact during rearing [an additional 12 min of human contact per day (AC) or no additional contact (MC) during rearing]; handling quality in adulthood [brief daily exposure to positive (+ve) or negative (–ve) visual contact with a human]; and handling proximity in adulthood [handling-quality treatment (+ve or –ve) imposed at the following three distances from the birds: Near, 0–45 cm; Middle, 45–75 cm, or Far, 75–105 cm]. AC during rearing resulted in reduced avoidance behaviour of humans during adulthood, whereas handling imposed at the Far level resulted in greater avoidance behaviour than did handling at the Near or Middle level. The quality of the handling (+ve or –ve) had little effect on avoidance behaviour; however, there was a trend (P = 0.07) for hens receiving +ve handling to have a lower corticosterone response to human contact than those receiving –ve handling. These results demonstrate that visual human contact can influence the avoidance behaviour of laying hens.