Effect of Population Density on the Pituitary-Adrenal Cortical Axis of Cockerels

IN RECENT years there has been considerable interest in the effects of crowding on broiler production. Tomhave and Seegar (1945) found that decreased floor space resulted in lower body weight, increased mortality and poorer feed conversion. Heishman et al. (1952) reported no significant differences in the number of culls, mortality, cannibalism or dressed quality as area was reduced from 1.0 to 0.5 square foot per bird, but body weights were reduced as population density increased. Although viability was good in New Hampshires and crossbreds, Hartung (1955) noted a reduction in “Grade A” carcasses in more concentrated flocks. Siegel and Coles (1958) found no significant differences in the weights or feed conversions of broilers grown at floor space levels ranging from 0.5 to 1.25 square feet per bird. It seems probable that much of the contradictory nature of these reports may be the result of differences in genetic stock and management …