Comparison of Individual, Sire Family, and Index Selection for Short Term Rate of Egg Production in Chickens

Efficiencies of index, individual, and sire family systems of selection were compared in the 9 to 11th selected generations. The criterion of selection was short term rate of production. Results agreed with those reported for the first eight generations in that standardized gains of the individual system exceeded those of the other systems. This disparity with expectations was attributed to the failure of experimental procedures to meet the assumptions of theory, inherent differences in inbreeding produced by the different systems, and random genetic drift.