Mice go in heat about every 5 days. A good breeder male usually takes no more than two weeks to get them pregnant. Gestation is 21 days. I remove the boys at 4 weeks of age to ensure they don't get anyone pregnant. I like to control my genetics and ensure that the best breed together. For the best health of the doe, most show style breeders wait a month before breeding her. The babies are fully grown at 3 months of age, but frozen "adult" mice tend to be younger. At three months, start breeding the does. A doe gets retired after her 3rd litter, so within a year of birth. This is the method used to ensure the top health of the mice. However, it does reduce the production. Additionally I only allow a doe to raise 5 or 6 babies at a time. The rest are fed off before fur starts to emerge, so the first few days. My suggestion is to start slow, decide what method you are most comfortable with, and increase production as needed. You don't want to feed mice everyday. Some ferrets will get tired of eating them. Variety keeps things tasty.
jadeguppy I don't normally share my suppliers because I do run a shop but if you throw me a PM I would be happy to share a place I get critter things. At wonderful pricing and shipping is super cheap as well. Because I appreciate what you do.