Impact of stocking density, breed, and feathering on the prevalence of abdominal skin scratches in broiler chickens

Associations between abdominal skin scratches and stocking density, strain of birds, and degree of feathering were investigated in a clinical trial. Four hundred eighty 1-day-old male broiler chicks from two different strains (A and B) were assigned to four groups: 1) high density (0.07 m(2)/bird) and strain A, 2) high density and strain B, 3) normal density (0.14 m(2)/bird) and strain A, and 4) normal density and strain B. Birds were examined for scratches and feathering at 28, 35, and 42 days of age. Two outcomes were considered for scratches: presence (yes/no) and severity (severe [if a deep cut or at least three superficial cues were present]/not severe). Only the examination at 35 days of age was blind. The outcome ''scratches'' was significantly associate. with stocking density at all ages (P less than or equal to 0.0001), strain A at 28 days of age (P = 0.0480), and poor feathering at 35 days of age (P less than or equal to 0.0001). The out come ''severe scratches'' was significantly associated with stocking density at 35 (P = 0.0003) and 42 days of age (P = 0.0021), strain A at 35 (P = 0.0089) and 42 days of age (P = 0.0306), and poor feathering ac 35 days of age (P = 0.0018). Stocking density, strain of birds, and degree of feathering could be considered as potential risk factors for abdominal scratches in broiler chickens.