Sex, Genetics and Test Type Affect the Responses of Chickens to Fear Testing

摘要

Background and Objective: Fear tests are often used as tools to evaluate the welfare of poultry under both experimental and commercial conditions. However, responses to these tests could be affected both by the genetic makeup and the sex of the individuals tested and in addition different fear tests may vary with respect to their validity and repeatability. The objective was to determine if genetics and sex affected fear response in two different tests. Methodology: Males and females of six different genetic stocks of fowl were tested using two fear tests, tonic immobility (TI) and inversion (INV). The stocks were Red Junglefowl, Red Junglefowl/New Hampshire Red crosses, three different Single Comb White Leghorn (SCWL) stocks (UCD-003 and Hyline CV 20) and genetically featherless (scaleless, SL) chickens. Results: There were pronounced genetic effects on all TI and INV responses, with significant differences among stocks although these were not necessarily consistent across all measures. Sex differences were more consistent than genetic differences, with males of all stocks showing. Males and females also differed irrespective of genetics, with males requiring fewer induction attempts and having longer latencies to first head movement and to right than females in the TI test (pConclusion: These results demonstrate that different genetic stocks of fowl react differently in different fear tests and that single fear tests should not be used to evaluate the fear response of fowl.