A contact dermatitis of broilers--epidemiological findings.

Lesions of a contact dermatitis have resulted in serious downgrading of broiler carcases in the Northern Ireland poultry industry. A longitudinal survey was initiated to identify the important epidemiological factors involved in the occurrence of the condition. The results from the analysis of data from 986 flocks containing 12.6 million birds over a 2 year period, have quantified the effects which the major aspects of production have on the incidence of the condition in individual flocks. The stocking density, feed manufacturer, average age of removal and the sex of birds all had a profound effect. Lesions were more frequently recorded in flocks during the winter months and a strong correlation with the weather variable, relative humidity, obtained. Individual producers and houses varied in the incidence of the condition which was closely associated with the presence of poor litter conditions in the flocks.