Temporal effects of mirror-image stimulation on pecking and peeping in isolate, pair- and group-reared domestic chicks

Abstract

The pecking and peeping behavior of isolate, pair- and group-reared chicks tested singly with and without mirrors were studied during 2-hr tests. Results supported the hypothesis that the social facilitation of pecking is disrupted by test novelty (discrepancy between testing and rearing conditions). Mirror exposure resulted in the greatest enhancement of pecking and least peeping in pair-reared chicks and in more moderate pecking increases and more peeping in group-reared chicks. Isolates initially avoided mirrors but after an hour peeped less and showed a social facilitation of pecking.