Unwanted Baby Mice

Question
Hi, I got three female baby mice just over a week ago, the seller, a private seller, said the female mice were separated from the males early on. However a week last and I have three new babies on top of the three females. I have never had mice before so am worries that I won't cope with 6 mice. I don't know how to sex them and the three adults aren't very tame so to handle them and check would be difficult. I'm worried that the babies will need to be separated (Male/female) when they are 3/4 weeks but I don't have anywhere to put them. I currently have them in a largish fish tank which is ideal but I only have a small travel case for them which would be too small for the boys to live in. Would would you recommend with separating them? I would like to rehome them but all the pet shops round here said people aren't buying/selling them atm so I'm worried I'll be stuck with 6 mice and they will breed more.

Also they are using their wheel as a toilet. It smells lots as it doesn't absorb the mess like sawdust. How do I stop them using it? I tried rinsing it and leaving food in it regularly but they just move the food out the way.

Answer
Dear Julia,

This is a common predicament.  It's unfortunate it was a private seller who misled you-- I assume there is no possibility to return some of the mice now.

You can try to rehome mice through an online forum such as Craigslist, depending on where you live; want ads in a newspaper or circular; or putting ads on bulletin boards at public libraries or other meeting places.  One idea is to call up the science department in local middle or high schools (or any elementary school teacher) and see if they would like a class mouse. Start this now; don't wait until the mice already need homes.

In the meantime, you should be handling the babies once they are 7 days old.  Take the mother mouse out of the cage (using a toilet paper roll to catch her) and place her in your carry case for the five minutes it will take to take out the babies and handle them together just for a few minutes.  Work up to 5 minutes per baby mouse 1-2x a day by the end of 4 weeks.

Use this guide to sex the babies starting right away (so you become confident).

http://www.thefunmouse.com/info/sexing.cfm

You will separate the sexes at 4 1/2 weeks.

The more girls you have, the luckier you are, because girls can all live together.  Boys may end up in separate cages in the end because they may fight.  Separate fighting mice when there is blood.  However, you still have a little time between separating the sexes and having to separate the boys; they won't get vicious right away.  Sometimes litter mates can live together peacefully forever.  

As for the wheel problem... mice like the way they smell (to a certain extent; they also like to be clean), so they especially like the fact that when they use the wheel as a bathroom, it smells lots stronger than if they used the litter.  This isn't an easy habit to break, and likely the whole cage will have the same habits.  Try to think of it as making it easier to get the smell out of the cage, since it's so easy to take the wheel out and clean it...

Tip:  If you can give away some of the mice, keep the ones you have hand-tamed instead of the originals, so you have tamer mice.

Best of luck.

squeaks n giggles,

Natasha