The amount of cage bedding preferred by female BALB/c and C57BL/6 mice

In order to improve the welfare of laboratory mice, a number of different environmental enrichment strategies have been developed to provide opportunities for mice to engage in naturalistic behaviors. Providing sufficient cage bedding for mice to use as a burrowing substrate could be considered an environmental enrichment strategy, but few studies have considered the welfare aspects of cage bedding amount. The authors compared the preferences of group-housed female BALB/c and C57BL/6 mice for three different volumes of cage bedding (0.5 l, 1.5 l and 6 l). Mice of both strains but especially C57BL/6 mice showed strong preferences for cages with more bedding. The results highlight the importance of providing a sufficient amount of cage bedding to laboratory mice.