Headshaking in fowls: The effect of environmental stimuli

The incidence of headshaking in domestic fowls (Gallus domesticus) is influenced by both social and environmental factors; it was more frequent in larger groups and in subordinate birds, and it could be greatly increased by exposure to disturbing stimuli. The findings are not readily explained by earlier suggestions that it is a response to frustration of movement, that it serves to increase sensory input under conditions of social isolation in barren surroundings, or that it is a displacement reaction to conflict situations. Evidence is presented to show that it occurred in contexts demanding increased attention, for example, upon the presentation of novel or disturbing stimuli, and it is proposed that headshaking is an “alerting response”.