Cross-sectional study of the prevalence of feather pecking in laying hens in alternative systems and its associations with management and disease.

A cross-sectional study of risk factors for feather pecking in layings hens in alternative systems was carried out in July 1998. A total of 637 questionnaires were sent out to farmers and producer groups and, after two reminders, the final response rate was 51.5 per cent. The outcome variable was feather pecking after point of lay. Over 55 per cent of the farmers reported that feather pecking had occurred in the last depopulated flock. This outcome was compared with the management procedures reported by flock managers by using univariate statistics. Factors associated with feather pecking with a significance < or = 0.05 were then tested in two logistic regression models. In the first model the following factors were associated with an increased risk of feather pecking: less than 50 per cent of the flock using the outdoor area on a fine and sunny day, the occurrence of egg peritonitis and the occurrence of infectious bronchitis. The direction of the association between feather pecking and these infectious diseases was unclear, so in the second model only factors which were consistent throughout the laying period were tested. The following factors were associated with an increased risk of feather pecking: less than 50 per cent of the flock using the outdoor area on a fine and sunny day; three or more changes of diet during lay; the inspection of the flock by one person; an absence of loose litter at the end of lay; a temperature in the hen house of less than 20 degrees C; turning the lights up when the flock was inspected; and the use of bell-drinkers. It is concluded that some of these factors could inhibit foraging and dust-bathing behaviour and others may increase competition or frustration, both of these changes having been shown experimentally to initiate feather pecking behaviour.