The effect of early life experience, environment, and genetic factors on spontaneous home-cage aggression-related wounding in male C57BL/6 mice.

Aggression is a major welfare issue in mice, particularly when mice unfamiliar to each other are first placed in cages, as happens on receipt from a vendor, and following cage cleaning. Injuries from aggression are the second leading cause of unplanned euthanasia in mice, following ulcerative dermatitis. Commonly employed strategies for reducing aggression-related injury are largely anecdotal, and may even be counterproductive.