introducing field mice

Question
i catch field mice from work and keep them as pets.  they are black as babies, but turn brown with white belly when they mature.  i am curious how often you deal with fighting.  currently I have 2 males in 1 cage from the same litter and they get along and accept other mice, but i don't leave them.  i caught 3 last week, 2 males and a female. they got along till the female claimed the bed and forced me to separate the males. yesterday I caught 2 females and they got along until i gave them a bed and one bite the other killing her.  

my main question is how do you socialize your mice?  i want to find a cage to separate them, but keep them in one till they get used to each other without them attacking each other. do you have any suggestions?  I have about 10 cages, but want to be able to combine them into males and females to give them friends and more things to do.

i know pet shops just resupply by dumping more mice in, but i never found mice that the others would attack and kill.

Answer
Dear Joe,

I am having a hard time following your story.

"they got along till the female claimed the bed and forced me to separate the males. yesterday I caught 2 females and they got along until i gave them a bed and one bite the other killing her.  "

I don't under stand what you mean by 'bed.'

I do understand that you have mice who fight and you would like to have them get along and live in one all-male cage and on all-female cage. With fancy mice that people keep as pets, the males do not live together, but I have heard that it is easier with other breeds. Certainly they will all be happiest with friends.

There are number of methods you can use. I think the following is the best scenario:

Every night for a week, swap out some of the bedding between the cages of mice you want to eventually put together. Just change the bedding around so each mouse smell the others in their cage.

Next, in the morning,  take some REAL vanilla extract (not essence) and put a dab on their necks and rumps to make them all smell the same. Take one small cage and clean it thoroughly. Put nothing in but one very obvious nest, a water bottle, scattered food, and a lot of toilet paper rolls. Put all of the mice in at once. Do this when you are home. Observe.

It is ok if they run around and chase each other and squeak. This is quite normal. The only reasons to separate are:

1. if there is blood.
2. If a mouse is clearly terrified or depressed after a day.
3. If a mouse is blocked from the water bottle or nest.
4. If the chasing and squeaking really does not stop.

Once this has gone well for a few days, you may put them in a cage big enough to put a couple of wheels in and use a food dish. Only when they have passed the test of sharing a few cage items are they ready to share a big cage and lots of toys. There should always be multiple wheels with multiple mice.

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However I have a question. Why are you keeping these mice as pets? No uninjured wild mouse wants to live in a cage. I hope you have at least a 40 gallon aquarium for them because they need space. And a lot of wheels.

Best of luck with them.

Squeaks n giggles,

Natasha