AGE-RELATED CARCASS COMPOSITION CHANGES IN MALE BROILER-CHICKENS

To quantify growth and development of the broiler chicken to 70 d, a flock of male birds was sampled at regular intervals, and observations were made on growth and development of various carcass components. Birds were fed conventional diets and maintained on litter-floor pens in a room with environmental control. At 21, 28, 35, 39, 43, 47, 50, 55, 60 and 70 d of age, 12 birds were selected at random for estimation of liveweight, eviscerated weight, cut-up portion composition and deboned meat yield. Observations involved weights of the various carcass components and proximate analysis. Birds showed linear growth to 70 d (P < 0.01), while development shown by the eviscerated carcass was positively quadratic (P < 0.01). Proportional fat content of the eviscerated carcass increased over time (P < 0.01), while protein content decreased (P < 0.01). The leg-thigh portion yielded the greatest quantity of meat, while the bone portion increased from 130 g to 843 g over the 21- to 70-d period. Total carcass skin increased in weight from 50 g to 365 g over the same period. Both deboned breast meat and leg meat increased quadratically over time (P < 0.01). Comparison of results with that developed 10-15 yr ago indicates chronological changes in carcass development. An apparent sporadic increase in yield of breast and thigh meat, which has also been shown by other workers, warrants further investigation.