Chick colour approach preferences are altered by cold stress; colour pecking and approach preferences are the same.

Colour approach preferences in 1-day-old New Hampshire and White Leghorn chicks were assessed by choice preference tests between pairs of differently coloured floors, illuminated by light passed through different interference filters and adjusted to equal luminance. In experiment 1, the preferences found closely resembled colour pecking preferences reported previously for domestic chicks, e.g. a preference for blue over green. Experiment 2 showed that the latter preference could be reversed by cold stress. That is, chicks tested similarly but in a cold noisy room (18.9 C) preferred green over blue. Experiment 3 eliminated the role of noise in this reversal effect, since chicks tested in a warm noisy room showed the normal blue over green preference. It was concluded, in disagreement with prior findings and their interpretations, that chick colour pecking and approach preferences are normally the same, not different, and certainly not spectral mirror-image reversals. Instead, a more restricted preference reversal (i.e. in the blue-green spectral regions) occurs as a result of cold stress.