Risk Factors for the Occurrence of Feather Pecking in Non-Beak-Trimmed Pullets and Laying Hens on Commercial Farms

Severe feather pecking (SFP) is a behavioral disorder, for which there are multifactorial reasons. Various aspects of pullet and laying-hen husbandry-including housing conditions, management, feeding, and genetics-must be considered, to prevent negative outcomes, such as severe plumage damage, skin injuries, and high mortality rates due to SFP. The aim of this study was to identify housing and management factors in the occurrence of feather pecking, so as to reduce the risk of this behavioral disorder in non-beak-trimmed laying hens on commercial farms with aviaries. Beak trimming may reduce the extent of plumage damage, but it does not prevent feather pecking and cannibalism. Thirty non-beak-trimmed flocks (16 in the first, and 14 in the second laying period) were investigated on 16 commercial farms in Germany. Each flock was visited twice during rearing, and three times during the laying period. During each visit, individual plumage and integument scoring were performed, and data were collected, regarding the housing and management conditions of the flocks. To analyze the influence of management and housing on the plumage condition of the rearing and laying flocks, models were calculated, using univariate multifactorial analysis. In the rearing period, high stocking density and poor litter quality were significant risk factors in plumage damage due to SFP. In the laying period, a lack of free range, poor litter quality, insufficient enrichment, and plumage damage during rearing were significant risk factors for the development of SFP. An individual risk analysis of pullet and layer farms is therefore strongly recommended, to prevent outbreaks of SFP and cannibalism, especially in non-beak-trimmed birds.