Behavioral correlates of male mating success in a multisire flock as determined by DNA fingerprinting.

The fertility of an individual rooster within a multi-sire flock may be influenced by a number of behavioral considerations, including frequency and timing of matings and the male's position in the social dominance hierarchy. The relationship between behavior and fertility has proven difficult to assess, however, because there are a limited number of heritable morphological traits that can be used to determine paternity. The objectives of the present study were to use DNA fingerprinting to determine paternity in domestic fowl and to assess some behavioral and physiological correlates of mating success. Sixty day-old chicks from each of two commercial breeds, DeKalb White Leghorn (L) and Warren Color-Sexed (W), were reared in either same-breed or mixed-breed groups. At 43 wk of age, all females and six randomly selected males were mixed into one large pen. Male aggressive and mating behaviors were recorded over a 4-mo period. Fertility of individual sires was determined by DNA fingerprinting and pedigree analysis of chicks. Dominance rank and the frequencies of both completed matings and mating attempts were positively correlated with fertility (P less than .01). In addition, wing flapping was correlated with both dominance (P less than .001) and fertility (P less than .05). There was no correlation between fertility and plasma testosterone. There were breed effects on dominance status, with W dominating L. Multiple paternity was demonstrated in 4 out of 10 families by DNA fingerprinting. The present study is the first one to demonstrate a correlation between dominance and fertility in a flock containing several males of the same breed and morphology.