title: Effects of grouping and isolation on feeding, food conversion and energy expenditure of domestic chicks.
abstract: At ambient temperatures of 25-30°C, domestic chicks gained more weight between 6 and 10 days of age when kept in groups of three than in isolation. This difference in growth rate, which was not affected by variation in social environment before testing, was due to a difference in food conversion efficiency only, and not to one in food intake. The only evidence of social enhancement of feeding was a temporary increase in feeding activity (but not food intake) shown by grouped chicks previously kept in isolation. The consistent difference in food conversion between grouped and isolated chicks was not due to differences in activity levels, digestibility, emotionality or stress, but was associated with a difference in metabolic heat production, or heat loss. Although there was little evidence of huddling by grouped chicks, their heat production was lower than that of isolates at ambient temperatures of 20 and 25°C, but not at 30 and 35°C; and the difference in food conversion efficiency disappeared at 35°C. It is concluded that isolates lack the opportunities that grouped chicks have for behavioral thermoregulation, but that all chicks achieve equal status energetically when the ambient temperature lies within or near the zone of minimal metabolic rate.
authors.affiliation: Agricultural Research Council's Poultry Research Centre, King's Buildings, West Mains Road, Edinburgh EH9 3JS Great Britain.
authors.forename: C
authors.initials: C
authors.lastname: John Savory
authors.forename: M G
authors.initials: MG
authors.lastname: MacLeod