Dominance Ratios Research Articles

Social Tension Indexes and Egg Production Traits in Chickens ,

CORRELATIONS between peck-order ranks of individual hens in flocks and various production traits have been reported (Sanctuary, 1932; Guhl, 1953; McBride, 1958; and Tindell and Craig, 1959). Peck orders become difficult to establish as flock size (N) increases, as there are N(N-1)/2 pair relationships involved. Determination of peck-order rank may be impossible in large groups of hens because of territorial behavior (McBride and Foenander, 1962; and Craig and Guhl, 1969).“Dominance ratios” (number of agonistic interactions dominated)/(total agonistic interactions) times 100, and “social tension indexes” (number of aggressive minus number of submissive acts) both have been used to characterize agonistic behavior of individual pullets in flocks by Craig and Guhl (1969) and by Craig et al. (1969), respectively. These estimators appear suitable for use in large flocks as they may be determined without working out the peck order.Social tension indexes appear preferable to dominance ratios from the statistical…