Effects of housing conditions on food intake, body weight and spontaneous lesions in mice. A review of the literature and results of an 18-month study.

Abstract Mice were housed in groups of one, two, four or eight/cage for 18 months. The more densely housed groups showed markedly reduced food consumption, slightly decreased mean body weights, and a smaller variance of body weights. Tumour incidence was not affected, but gastritis was more prevalent in the more densely housed groups.