Environment and Poultry Breeding Problems

INTRODUCTION DURING the past decade, the value of control populations to provide standard material for the evalution of the level of management in selection programs has become increasingly apparent. Control strains have been used extensively in laboratory investigations over a much longer period, and their usefulness amply demonstrated. Only recently, however, has the expense involved in their maintenance been considered worthwhile in breeding research involving poultry. Goodwin, Dickerson and Lamoreux (1955), Gowe and Johnson (1956), Skaller (1956) and King (1958) have given limited information on particular control flocks currently in use in selection programs. A detailed analysis of the results for one particular control flock has been presented by Gowe et al. (1959). It is the purpose of this paper to discuss in theoretical terms various problems arising in the maintenance of control flocks, and to set out the relative merits of two general types of design.