It has been suggested that feather pecking becomes widespread in groups of birds because it is socially learnt. However, a bird pecking the feathers of another seldom gains obvious extrinsic reinforcement for this behaviour (the feather is not always eaten, or material pecked from the plumage). Two aspects of social learning that have received little attention are whether reinforcement of the bird performing the behaviour (the demonstrator) is required for the watching bird (the observer) to learn, and in addition, whether single or multiple exposures to the behaviour are required. In two experiments we used a model behaviour - operant key pecking - to examine the effects of reinforcement of demonstrators (experiment 1) and the effectiveness of repeated demonstrations (experiment 2) on social learning by domestic hens.