The effects of regular handling on fear responses in the domestic chick.

Reduction of fear in the domestic chick by regular handling was assessed and an attempt was made to determine whether such an effect was due specifically to reduced fear of human beings or to a general reduction in fearfulness. Regular handling decreased the tonic immobility response, a fear-potentiated phenomenon, and increased approach to a human being, but had no effect on approach towards an inanimate object. These findings were common to three strains (two layer, one broiler), and suggest that handling does not depress general fearfulness, but specifically reduces fear of human beings, presumably through habituation.