Precocial Sexual Behaviour Ontogeny of Sexual Behaviour in the Domestic Cock (Gallus Domesticus)

International audience ; The young chicken shows spontaneous sexual responses towards its congeners. These responses have been studied with the aid of models, stuffed chicks mounted in the usual resting lying posture. Chicks, divided into groups and reared under different social conditions, were confronted individually (after temporary separation from their congeners) with a model of the same size. In the course of these tests all the young cocks showed distinct copulatory behaviour on the model, in the first month after hatching. These behaviour patterns appeared in certain young cocks from the age of 4 days and did not require any experimental raising of the level of androgen. For each one of the experimental groups, the time of appearance of the various elements of the precocious sexual behaviour varied according to the social environment (in which the individuals were raised) and to the duration of the period of separation from congeners prior to the tests. The young females never showed copulatory behaviour of the male type but exhibited dust bathing in the proximity of, and searching for contact with, the model. The comparison of the sequence of sexual behaviour of a very young cock with that of the adult reveals the absence, in the young, of the waltzing and of the fully organised sequences of tid bitting and cornering. These elements of intercommunication, which may ensure approach and allow mating between the adult cock and hen, only become established, in the cockerel, after the establishment of true copulatory behaviour. Furthermore, the copulatory behaviour of the young cock is suddenly coordinated in a correct fashion; in the same axis as that of the model. A hypothesis attempts to interpret examples of deformation, in adults, of the scheme of coordination of sexual behaviour reported by other workers (and personal observations).