Shelter
When choosing a shelter, IT MUST BE ESCAPE-PROOF. If
it's not, you will have rodent problems and any free-roaming carnivorous
pets you have will have a new plaything. In the case of pregnant mice,
this is not good. A fishtank with a screen mesh top is good because if
the tank is deep enough, you only need the mesh top to keep the cats/ferrets/dogs/etc
out. On the other hand, the mesh top keeps the rodent from climbing the
water bottle rack to freedom.
A birdcage can be an option, but only if the bars are too close together for a child to stick his fingers through. Lining the interior walls of a birdcage with window-screen mesh can be a solution, but be aware the the mice will climb it. They will also find a way to kick soiled bedding out of the cage.
When selecting the size of the shelter for your mice, remember that mice can produce litters of up to 15 at a time.
Screen mesh should be aluminum, not plastic. Mice will chew on anything they can get their teeth through.
About Food
I feed my mice the cheapest "gourmet" hamster food I
can find, a seed mix that includes kibble and sunflower, pumpkin, and peanuts. Adult mice can survive on just dog food, but it leads to malnutrtion in pregnant
and nursing mice, resulting in runt offspring, if any. After my last lean period, I had a month-old baby mouse who was the only survivor out of a
litter of 12 still nursing and the same size as his week-old siblings
from the following litter, born after I was finally able to get some real food for them. Since I am trying to produce full grown mice large enough to provide a good meal for a 52" ball python, this is of some concern to me. Seeing the sort of malnutrtion that young mice suffer from a prenatal/parental diet of dog food, I can guess that the adults' life span might be shortened after a while.
If you can get it, mice love Monkey Chow. Mine prefer it to regular rodent mix.
Water
Mice generally urinate and defecate without regard to
cleanliness. An open dish of water is not the best option.
I prefer to use 8-oz hamster bottles. I have used food dishes to provide water, but it has quickly gotten fowled with offal and bedding.
The spring on a standard bottle holder should be replaced with a solid wire, as mouse toes can and do get caught in the spring.
Heat
Mice should be kept at room temperature (60F-80F). Mice do not sweat. A pop bottle filled with water and frozen, then placed against the side of the cage, makes a good cooler on hot days. If you put the bottle inside the cage, the mice will try to eat it. If your mice are in glass tanks, keep them away from the windows. If your rodent room is prone to being cold, throw empty paper tubing or an old sock in the cage. They will cuddle up for warmth anyway.
Reproduction, etc.
The key phrase in a mouse's life cycle is "three weeks."
Mice gestate in roughly three weeks. They reach puberty in three weeks. They are full adults at the age of 6 weeks. It is possible for mice to be first-time parents at nine weeks. A normal life span for a mouse is at least 18 months.
Mice are quite comfortable sharing one male among two or three females. The females will keep their offspring in a communal nest, where older sisters from previous litters will tend the younger litter, keeping them warm while the mothers go off to eat and drink. The mothers are not selective of who they feed, as long as it's a youngling who isn't too old for the nonsense. Occaisionally, in small family groups, Papa Mouse will take a turn in tending the litter. I try to keep male offspring sorted out.
Handling
I try not to disturb a mouse through handling until it is at least a week old, and then only for cage cleaning or transfer. My mice have learned to tolerate being scooped up through weekly cleaning. I gain their trust by holding them in an open hand, so they can see that they have either an easy escape to their hiding place in the cage or the option to climb up my arm and have a better look at outside.
Most mice react badly to being trapped, usually by biting. If a mouse is determined to avoid my hand, I pick it up by the tail. I generally aim for the middle of the tail, closer to the base than the tip. If you must do this, remember that they will thrash around. Move quickly.
I have found that mama mice do not like their nests disturbed during the first 4 days of post-natal care. They get very agitated, and may abandon their offspring entirely. Wait until the fur grows before touching the babies.
Weird Mouse Tales
Militant Lesbian Mice
At one point, I was trying to set up a new family tank. I had 3 females and I tried introducing a male. They killed the intruder. I introduced a second male. They killed him, too. I threw in two males and a female, hoping to overwhelm them into accepting the intruders. They killed the males, but let the female live. I ended up giving up on breeding them and designated them as food.
The second water bottle is a chew toy
I tried putting in a second water bottle in a feeder tank that had over 30 mice. They chewed a hole in it. After the second chewed bottle, I gave up and resigned myself to refilling the bottle twice per day. This trend continues even though all the original culprit mice are gone.