Cage litter should be changed at least once a week. There has been some debate about whether cedar and pine shavings cause respiratory illness in rats and mice, so it is best to use a synthetic or other type of litter. Rice, grains, animal proteins and prepared rat foods are excellent foods for rats. Individual mice can get quite lonesome and sleep a lot and become withdrawn, so it is best to have several mice. That way, their personalities balance each other, and they have someone else to help with grooming, a favorite mouse activity.
Female mice get along well together, whereas some males can be aggressive.
Unless you want even more mice, it is best to house males and females separately. Like rats, mice are ready to join a human family after five or six weeks. Mice cages need to be large enough so that each mouse has his own nest area for retreat and wheel for exercise. Cages should be at least 12 by 24 inches for two mice, although, unlike with rats, it is not necessary to have several levels. Like rats, their cages should be cleaned at least once a week.