Your mice will be healthier and live longer if you provide them with appropriate, well ventilated housing, a nutritionally sound diet, and opportunity to exercise and explore their environment. Good sanitation is the key to preventing many types of disease.
A wide variety of cages are available for keeping mice. In general, a cage should have good ventilation, be easy to clean, and be escape proof. A plastic cage or glass aquarium or terrarium of sufficient size can make a good home for mice. Metal cages are not recommended because they can allow drafts (through mesh openings) and collect condensation. Cages made with wood are unacceptable for mice, as their urine will soak into the wood. This causes ammonia buildup, which can lead to respiratory disease. Mice may also chew through the wood, allowing them to escape.
Cages must have wire mesh on the top for good ventilation. The wire should be fine enough to prevent escape and strong enough to resist chewing from adult mice. A mesh with 1-centimeter squares is the recommended size. The minimum cage size for 2 to 3 mice is 18 inches (45 centimeters) long by 18 inches (45 centimeters) wide by 10 inches (25 centimeters) high. The bedding and floor covering should be absorbent. Wood shavings or prepared litter can provide soft bedding for mice. Cedar or pine shavings should be avoided as they may irritate the mouse's respiratory system. Hay or recycled paper may be added. Mice are nest builders and will make nests from their bedding for sleeping.
Fresh water should be available at all times to prevent dehydration. A water bottle with a hanger that allows mice to easily access the water is recommended. Holders with chew guards for the water bottle are available. These allow you to hang the bottle inside the cage. A water dish or bowl should be used only in emergencies, as mice often will spill the water or push shavings in it. If you use a food dish, it should be easy to clean and sturdy enough to prevent tipping.
Poor environmental quality, such as high ammonia levels and poor quality bedding materials, can increase the risk of bacterial or viral infections in mice. Cages should be cleaned with hot water at least once a week and the bedding should be changed at least twice weekly. Fresh water and food should be provided on a daily basis. All dishes and water bottles should be thoroughly cleaned before refilling.
Mice need a balanced diet that includes carbohydrates, fat, and protein. Commercial mouse diets are available and not only contain all the vitamins and minerals that mice need, but are also hard enough to wear down their constantly growing incisor teeth. Fresh vegetables, sunflower seeds, and fruit can be given in limited amounts as treats. On average, an adult mouse will eat 3 to 5 grams of food and drink 3 to 5 milliliters of water daily. Mice should be fed once a day (at night) and all uneaten food should be removed before fresh food is provided.
Routine exercise is necessary for good health in all animals. Mice are extremely active and enjoy opportunities to exercise and play. Access to exercise wheels, tubes, ladders, and climbing blocks will fulfill this need. The cage should be large enough to accommodate some of these “cage toys” and allow comfortable movement around them.
Mice are very social animals, and they appreciate being in a group. However mice owners should be careful when male mice are placed in the same cage, because they tend to fight unless they grew up together. Unrelated female mice can normally be placed in the same cage without any problems.
Usually, mice are good pets for children. However, they should be kept away from other pets in the house such as dogs, cats, birds, and other rodents. Remember, mice are the natural prey for several of these animals!
Because mice are nocturnal, they can be quite active at night. You may want to consider placing the cage in a location where sleeping family members will not be disturbed by their activity.
Last full review/revision July 2011 by Katherine E. Quesenberry, DVM, MPH, DABVP (Avian); Kenneth R. Boschert, DVM, DACLAM