Environment and Poultry Breeding Problems

ALTHOUGH the use of unselected control strains in laboratory selection experiments with Drosophila and other laboratory animals is a well-established practice, only in recent years have workers interested in selection experiments with poultry and large animals given serious attention to the need for adequate controls. This lack of controls has made it difficult for the critical reader to interpret published reports on the effects of different selection programs with poultry and animals. The earlier selection experiments, with poultry, for example Pearl and Surface (1909), Dryden (1921), Hall (1934) and Lamoreux et al. (1943), would have been more readily interpreted if control strains had been maintained in the contemporaneous environments. It is even possible that some of the confusion arising from these early contradictory results would have been resolved. More recently Lerner (1950) has briefly discussed the value of control strains. He drew attention to the fact that his selection studies …