Effect of Inbreeding on 8-Week Weight in Chickens

During investigations for another purpose data were accumulated indicating inbreeding depression of 8-week weight in Athens-Canadian Randombred (A.C.R.) chickens. When inbred birds were compared with contemporary non-inbreds from a mass mating the inbreds were lighter in 31 of 34 comparisons. The differences are listed in Table 1. A search of indices in Poultry Science revealed only three published values of regression of body weight on inbreeding in chickens. Shoffner (1948) reported a non-significant estimate (−0.004 ± 0.003) of regression of mature body weight in pounds on inbreeding. Glazener et al. (1951) reported a significant estimate (−0.1297 ± 0.005) of regression of 12-week weight in ounces on inbreeding. Blow and Glazener (1953) reported another non-significant estimate (−1.044 ± 0.851) of regression of body weight at sexual maturity in grams on inbreeding. There have, however, been several estimates of regression of body weight on inbreeding in mammals. Some of these are tabulated…