Serotonergic mechanisms in control of stereotypies in fowls

Abstract

s /Applied Animal Behaviour Science 44 (1995) 257-281 261 domestic hens and a reward of five food pellets, showed that the hens run faster in frustration trials (44.1 f 4.3 cm s‘) than in rewarded trials (40.2 f 4.4 cm s-r; P= 0.006). Domestic hens produce specific calls when deprived of certain needs. We investigated whether hens (n = 16) uttered frustration vocalizations depending on the presence or absence of an audience (another hen next to the first goal box). In frustration trials in which hens were held for 30 s in the first goalbox, only a mild increase in vocalizations was found (P < 0.05 1) When hens were held for 10 min, a highly significant increase in vocalizations was recorded (alone, 0.51+0.15 vocalizations min-’ with audience; I .74 + 0.32 vocalizations min‘; P< 0.001). Frustration in domestic hens elicits an increase in activity, expressed in higher running speed in a double runway, and an increase in vocalizations in the presence of an audience.