The effects of social experience on imprinting in differentially housed domestic chicks: a multi-measure approach

Abstract

The purpose of the present study was to covary housing and training conditions and to determine their effects on imprinting to a 'vocalizing' model hen. Domestic chicks were housed either individually or in pairs. They were run over Days 2-4 post-hatch under one of the following conditions: alone, in the presence of an isolate conspecific, or in the presence of an unfamiliar 'socialate' conspecific. All chicks were then tested individually on Day 5 post-hatch with the stimulus-object present in the apparatus. They were again tested on Day 6 post-hatch with the stimulus-object absent from the apparatus. Approach latencies on Days 5 and 6 and degree of distress calling on Day 6 served as indices of imprinting strength. Based on the approach measure, in testing with the stimulus-object present, chicks trained alone obtained the highest imprinting scores; chicks trained with an isolate, the second highest; and chicks trained with a socialate, the lowest. Apparently, during training chicks are more attentive to a socialate than to an isolate conspecific, which is reflected in their lower imprinting scores obtained during testing. Based on the distress index, in testing with the stimulus object absent, socially housed chicks obtained higher imprinting scores than chicks housed individually. The differential detection of housing and training effects for the approach and distress measures is discussed in terms of the nature of the probable underlying relationship between strength of imprinted attachment and the behavioral measures.