Genetic Selection for Breast Width in a Strain of Rhode Island Reds

THERE are two basic reasons for attempting to breed poultry with a greater breast width. One is to increase the amount of breast meat and the other is to improve the appearance of the carcass by making it less angular. This problem has been under study for ten years or more by a number of investigators. Several methods for measuring breast width have been proposed. These include the ratio of shank length to the cube root of body weight (Jaap and his associates, 1938, 1939, 1941), subjective grades (Knox and Marsden, 1944, and others), breast width at one-fifth full body depth (Bird, 1945, 1948, and El-Ibiary and Jull, 1948) and the width at varying distances from the apex of a tracing of breast conformation obtained with a lead tape (Asmundson, 1944Asmundson, 1945Asmundson, 1948, and others). None of the methods has proved entirely satisfactory. The lead tape procedure, however, has given . . .