Tests in Different Environments of Fowls Genetically Resistant to Leucosis

THE extent to which strains of fowls bred for genetic resistance to disease can be generally utilized depends in part on the answer to an important question. Are such resistant stocks equally or similarly resistant when transferred to areas other than that in which they were developed? With respect to unselected stock, there is ample evidence that strains which are satisfactory when lightly exposed in one environment can experience high mortality when severely exposed elsewhere. There is little evidence, however, on the degree to which strains bred for resistance to disease maintain that resistance when transferred to some other region. This question is particularly important with respect to leucosis, because genetic resistance and rearing in isolation are the only means known for controlling that disease. To answer it, in part at least, an exchange of stock was arranged between the Alabama and New York (Cornell) Experiment Stations, at both of . . .