Leap orders in male chickens (Gallus gallus domesticus): longitudinal evidence

Leap orders in pairs of male chickens were traced in a longitudinal study from near hatching to about 11 weeks of age. Birds were given a series of 39 day-long social separations, each followed by a day-long reunion. Tests for aggression occurred during the first 5 min of reunion. Pecks were frequent early in the test series, but soon diminished; leaps supplanted pecks as the most frequent response at about midseries, and abated in turn. To account for this dual pattern of the waxing and waning of aggressive responses, it was hypothesized that leap orders had formed in midseries, thus obviating further agonistic behavior. Support for the hypothesis was found: Early peck orders did not predict later leap orders, but early leap orders did predict subsequent leap and peck orders.