The influence of sex, climate, and body weight on skin tears and muscle damage during plucking of broiler chickens

In regional and controlled studies, about 500 flocks, slaughtered over a 3-yr period, were tested for skin tears and muscle damage during defeathering. In the regional study, the influence of sex and climate on these variables was evaluated. In the controlled study, the effects of the growing temperature and the temperature at which the birds were held prior to slaughter on skin tears were investigated. Skin tearing and the resulting muscle damage was found to be a major problem in female chickens, but rarely appeared in males. Differences in muscle damage were related to seasons of the year. The degree of muscle damage following skin tears in the slaughterhouse increased with the number of hours that ambient temperature had been higher than 33 C during the growing period of the flocks. This result agrees with those of the controlled studies, which showed a similar effect of temperature during growth on skin tears. In contrast, holding temperature on the day of slaughter did not influence skin tear or muscle shredding rates. Body weight, age of marketing, and the physical form of the diet (pellets vs mash) had no effect on muscle damage during plucking