Number of affected cages and injured mice.

Mice were checked for wounds daily at cage checks and once per week during cage change. a) Number of cages with injured mice and the overall number of injured mice were higher in Balb/c strain. Number of injured mice is reported as relative to group size (three or five). B) In Balb/c mice, wounding occurred across the 12 week housing period, while in SWISS mice most wounding was seen after six weeks of housing. Boxplots show medians, interquartile ranges and 95% confidence intervals.