Assessment of fear in adult laying hens: correlational analysis of methods and measures.

The fear responses of adult laying hens of two lines, flighty and docile, were assessed in each of three commonly employed and widely differing test situations. These were the pen with cone, novel rod and tonic immobility tests. Each hen was ranked for fearfulness on each behaviour pattern recorded and was then assigned an overall 'fear rank' in each of the three tests. Significant intra-individual correlations were found in both lines between the ranked responses within tests and between the overall fear ranks assigned in each of the three test situations. The findings support the use of these tests as methods of assessing fear in adult laying hens and are considered to reflect the estimation of general underlying states of fear rather than stimulus-specific responses.