Anyone who is considering breeding rodents should just build a rack.

The medium Petmate litter pans (16" x 12" x 4") is really perfect for 1.2 mice.

Doggy Bag dog food is what I feed to my rats exclusively. Mice might need a little more fat if you are keeping them together all the time.

I wouldn't separate them. Just let them keep breeding. Try to keep track of when the babies are born and you can pull them at 28 days or when the next litter is born, whichever is sooner.

Also, I wouldn't cull any babies off the bat. If you have a small scale breeding operation you can check all of your tubs every day. You can pull the small, weak looking babies and feed them to something. The smaller weaker babies will die and will be eaten by the mom. Its better to feed them off before that happens.

When you build a rack for mice remember to use 1/4" hardware cloth.