Updated: Oct 28, 2022
One of the big questions new mouse owners have is where to put their new friends. There is a lot of conflicting information out there by all sorts of people. Well, now I'm going to be one of those people! I'm not only going by my experience and the experience of other breeders like myself, but also scientific research that I have dug through. If I find anything that contradicts my views, I will factor that into my suggestions. Mice are very small prey animals. Out in nature, they tend to move through tight spaces, only crossing open areas quickly when needed. As such, they do better in smaller spaces over larger spaces, and require places they can hide. The rule I go by is you want about 49 square inches of floor space per mouse. This allows space for them to move around comfortably without being overly stress. While you can go a bit larger, too large will be more detrimental than beneficial for your mice. Most commercial rodent cages either have bars that are spaced too wide, or lots of places to collect urine and stink things up. This makes finding the right housing pretty difficult. Mice need plenty of ventilation (though they shouldn't be kept directly in drafty space), but can squeeze through bars that are half an inch apart. Fish tanks and vivariums are an option, as long as they are not so tall that the bottom doesn't get air flow. I find these to be frustrating to clean, since they are very heavy and don't have a nice tray at the bottom to pull out and dump. My favorite mouse home is a bin cage. You can get commercially made lab bins if you want. Going with this route, you will want rat sized bins with bar spacing that is about 1/4 inch apart. They will last for a long time and have built in hoppers for food and a place to put a water bottle. They are FANTASTIC! A much cheaper and more versatile option would be to make your own bin out of a storage tub and 1/4 inch hardware mesh. There are so very many videos and instructions out there that include tips and ideas that I won't include them in this particular post.
If you want something extremely large and elaborate for your mice, I recommend you set up a play area apart from their main home. That way you can decorate to your heart's content, but your mice will have a comfortable home where they feel very secure when you aren't around. When you are setting up your habitat, there are several things you should keep in mind. A minimum of one hide should be provided. This could be store bought, or it could be a smallish cardboard box you got in the mail the other day. They also need enrichment. Again, this doesn't have to be fancy. A habitat with a food hopper (where food is kept outside of the cage and mice access it through bars) or treats hidden to make mice forage are both really easy enrichment options. Toilet paper and paper towel tubes are excellent items for enrichment, because they are a combination of a hide, a chew toy, and a climbing toy. Torn up or crumpled up brown packing paper is also a favorite of my mice! No need to spend a lot of money on this. There are also a lot of store bought options you can find if you would like. Many bird, rodent, and even cat toys can be utilized.
Lots of people want to put in a wheel or a spinner for their mice. It is a great addition, though it isn't required. Some mice love them, some just use them as a toilet. If you do choose to get a wheel or spinner, go with something 8 inches in diameter or more. The ones marketed toward mice are actually too small and can cause musculoskeletal issues. You can see this in the form of wheel tail, where the mice are so used to arching their spines the wrong way, their tail ends up permanently curled up over their backs.
Mice do well with fluffy bedding to dig and burrow in. My favorite is aspen bedding. Kiln dried pine is also a top performer. Many people use sweet PDZ, corn cob, or pelleted bedding under shavings to add extra ammonia absorption. There are tons of options out there, though, so you might want to experiment with what works for you. Whatever you end up with, I recommend at least a couple of inches deep. Some bedding I suggest you avoid are paper bedding and coconut coir. Paper bedding does not reduce ammonia as much as mice need. In one research study, Carefresh had to be discontinued part way through because the amount of ammonia spiked quickly to dangerous levels. Coconut coir does well for ammonia control, but has other problems. When it is dry, it is very dusty and can cause lung issues. When damp, it has been known to wrap around limbs and then shrink as it dries, which causes loss of circulation and can amputate limbs.
Cleaning and maintaining your housing is crucial, both for the sake of your mice, and the sake of your nose! Once a week cleaning should be all you need. Any more often than that could cause your mice to start marking more than usual, which will only make your habitat smell faster. You can spot clean excessively soiled areas if you find the habitat gets too smelly. Every time you clean, you should remove the soiled bedding and any hides or toys that are porous, such as toilet paper tubes and cardboard boxes. At least once a month, you should wipe down the habitat with a gentle cleanser. If you use anything harsh, such as disinfectant wipes, it is VERY IMPORTANT to let any chemicals off gas before putting your mice back. I find mild dish soap works well, though, so that is what I use. Once your habitat is clean, put in fresh bedding, hides, and any toys or enrichment you have.
Food and clean water should always be available for your mice. Mice have very fast metabolisms, so they do well with free feeding. Food can be given in a hopper, in a bowl, or scattered around for them to forage. Chances are, if you put the food in a bowl it will be spread around anyway. This is normal mouse behavior. Their main source of food should come from a high quality rodent block, with other things being added as occasional treats if you would like. This way they get balanced nutrition and can't just pick out their favorite things. My brand of choice is Mazuri, since it has great ingredients and even something to reduce the smell of mouse urine. Water bottles are far preferable to water bowls. Mice tend to cover water bowls which results in very dirty water that needs to be changed multiple times a day. If for some reason you want to go with a bowl, having a platform will help. If the bowl is off the bedding on the ground, your mice will be slower to make a mess of it and you might be able to get away with only once or twice daily water changes. Bottles just need to be refilled as they approach being empty. I hope this helps you feel a little more confident while you prepare for your new mice!!!
Updated Oct 2022