Range and confinement rearing of four genetic lines of turkeys. 2. Effects on behavior and tonic immobility.

An experiment was conducted to determine the effect of range and confinement rearing on behavior and tonic immobility of four genetic lines of turkeys. Lines of turkeys utilized were selected for increased body weight, or increased shank diameter, or were randombred control lines developed in 1966 and 1986. Birds from the four lines were brooded lines and sexes intermingled to 8 wk of age in confinement. At that time, half the birds from each full-sib family were moved to a large range pen and the remaining birds were moved to a large confinement pen. Selection for increased body weight has resulted in an increased number of eating bouts, decreased duration of walking bouts, and greater fear response (as measured by tonic immobility inductions and duration). Rearing environment affected drinking, eating, and resting behavior. Range-reared birds had fewer drinking bouts of increased duration, and longer eating and resting bouts than did their confinement-reared contemporaries. There were no line by environment interactions, indicating that the four lines responded similarly in both rearing environments.