Effects of domestication on filial motivation and imprinting in chicks: comparison of red junglefowl and White Leghorns

Domestication has been reported to reduce learning ability and to alter social behaviour. We compared the development of filial behaviour of domestic chickens, Gallus gallus domesticus, and the ancestral red junglefowl, Gallus gallus. We investigated the tendency of naïve chicks to approach conspicuous stimuli, as a measure of filial motivation, and the development of a preference for familiar stimuli over unfamiliar ones, as a measure of imprinting and hence of social-learning ability. Chicks were placed in an arena containing two stimuli (a red cylinder and a blue ball) after being housed individually with one of these stimuli for 0, 6, 12, 24, 36, 48 or 60 h. During a 20 min trial, observations were made of their latency to approach each stimulus and the amount of time spent close to them. With no prior exposure to either stimulus (0 h), the breeds did not differ in their readiness to approach stimuli, suggesting no difference in filial motivation. However, the breeds differed in their initial preferences between the two stimuli tested and in their ability to imprint on them. Junglefowl chicks showed an initial preference for the red cylinder, but imprinted equally well on both stimuli, whereas Leghorn chicks showed no initial preference but imprinted relatively poorly on the red cylinder. We suggest that junglefowl chicks may be more flexible in their ability to imprint on stimuli than domestic chicks; however, a greater variety of stimulus types must be tested to confirm this.