Mice have a strong preference to nest away from their own waste, and mice in laboratories should be housed in a system of cages that allows them to segregate space into clean and dirty areas, according to work led by researchers at the University of British Columbia. Current standard laboratory housing for mice consists of small, simple cages where mice are in constant contact with their waste.
The new study, published in the journal Scientific Reports, showed that mice housed in a system of three interconnected cages carried their nesting material into one cage, which they kept clean, and carried their bedding material into another cage, which they used as a latrine. Compared to mice housed in standard laboratory cages, mice housed in these interconnected cages also expressed more behavioral indicators of good welfare and were less disturbed by weekly husbandry procedures. The study concluded that mice are willing to work to maintain a comfortable place to rest well away from their latrine. The researchers hope their findings will lead to improved cage designs for mice, allowing the animals to more easily perform their natural segregation behavior and thus improving their welfare.