This study examined the prevalence and incidence of abnormal behaviour in sheep housed individually indoors. Ninety-six castrated Merino sheep were observed using 15-min instantaneous sampling between 08:15 and 18:15 h for two consecutive days over a 3-week period. Sheep on average spent 62% of their time idle, 17% feeding, 1% drinking, 5% pacing, 10% chewing pen fixtures and 4% nosing pen fixtures. Pacing behaviour was predominantly seen in the morning with sheep on average spending 14% of their time pacing. Sheep on average spent 4% of their time in the morning and 13% of their time in the afternoon chewing pen fixtures. In the afternoon, the predominant behaviour was idle with sheep on average spending 71% of their time idle. Seventy-one percent of the sheep displayed one or more of the behaviours of pacing, and chewing and nosing pen fixtures for more than 10% of the day and 47% displayed one or more of these behaviours for more than 20% of the day. The prevalence and incidence of these 'abnormal' behaviours appears high, especially in relation to that of sheep grazed outdoors on pasture, and raises the question of the welfare risk to these animals. However, without a more comprehensive appreciation of other aspects of the animal's biology, such as stress physiology and fitness characteristics, it is difficult to understand the welfare implications of these behaviours.
Keywords: abnormal behaviour; individual housing; sheep; time budgets.