Mice need a spacious metal cage, or a glass or plastic tank. Cages should have a deep plastic base rather than a wire base which could damage feet. The bars of the cage should be close enough together (less than 1cm) to prevent escape. Tanks need a wire mesh lid with small holes for ventilation. Remember that mice have very strong incisor teeth and can chew their way through wood.
For two mice, cages or tanks should be at least 45cm long x 30cm wide x 25cm high. Allow a further 30cm for each additional mouse.
The cage or tank should be placed in a well-ventilated warm room away from draughts and direct sunlight or heat. Keep your mice away from constant noise (e.g. the hum of a fridge freezer) or loud noise (e.g. TVs or music systems).
Respiratory disease is common in mice. Selecting the right type of bedding can help to reduce respiratory problems. Wood shavings, sawdust and sand should be avoided. Cedar and pine wood shavings contain phenol whilst sawdust and sand tend to be dusty. Phenol and dust are both irritants to the respiratory system.
Line cages or tanks with newspaper and use shredded paper or cardboard, commercially available recycled paper bedding or hemp bedding. Make sure that the bed is deep enough to allow your mice to burrow.
A separate nesting area should be provided in a cardboard or plastic box where the mice can burrow out of sight to sleep. The ideal bedding for nesting is shredded clean white paper (e.g. kitchen paper) and soft hay. Avoid fluffy bedding such as cotton wool as it can wrap around limbs or cause impactions in the stomach if eaten.
Fresh water must be provided daily from a drip feed bottle with a metal spout.
Feed a good quality mouse mix based on mixed seeds and grains. Do not feed hamster food and avoid mixes containing lots of sunflower seeds and coloured corn flakes. Contrary to popular belief, mice do not need dairy products. Provide small pieces of fresh fruit (not citrus fruit) and vegetables and remove any uneaten food daily.
Gnawing is important to wear down incisor teeth. Dog biscuits (based on egg and oatmeal without meat derivatives), gnawing blocks or untreated apple wood are good for this.
Foraging behaviour can be encouraged by hiding food in cardboard tubes and under pots.
Mice like to climb so it is a good idea to provide different levels with shelves or baskets. Natural ropes can also be used for climbing in addition to gnawing. Cardboard tubes and egg boxes can be used for hiding, climbing and gnawing.
Activity wheels should be solid and wide. Wheels with spokes can trap limbs and cause injury. The wheel should be big enough that your mouse’s back doesn’t bend.