The basics of breeding
Pregnant stone satin doe
Does
Generally speaking, does can be bred from the age of 12 weeks. Some varieties that tend to become obese and therefore suffer from fertility problems are often bred slightly younger to counteract this - say from ten weeks or so. A doe will give you the best litters when she is still in her prime, so if you are going to breed from a doe then it is advisable not to leave it too long after 12 weeks before her first breeding.
Bucks
Bucks can breed from the age of five weeks or so and remain fertile until they die. Only one buck should be used per cage when mating up, or the bucks will fight over the does. Each buck can be placed with up to three or four does at a time and should be removed when the does are seen to be pregnant and before they give birth.
Gestation
Pregnancy in mice lasts 19-21 days - in my experience it is most often 21 days.
Litters
Litter size varies with the age of the doe, the variety and particular strain. While mice can have over 20 babies in one litter, the average size is more like 10-12. The young are born without fur and with their eyes and ears closed. The ears will gradually open over the first four days, and the eyes will open between ten and 14 days. Mothers with litters should be kept in solid-sided enclosures to avoid the young escaping. Babies are weaned at four weeks of age and bucks should be separated from their mother and sisters at this point to avoid pregnancies.
Rebreeding
I would recommend that does are given a break of at least three weeks after they have weaned their litter before they are bred again i.e. when their litter is eight weeks old. Condition is key however; some does may regain condition quickly and handle being bred again relatively soon, while some may never quite reach their pre-litter fitness again. Back-to-back breeding is not something I would personally recommend as I feel that mice do better and produce higher quality offspring when they have the time to build back up after the stress of rearing a litter.
Generally speaking, does can be bred from the age of 12 weeks. Some varieties that tend to become obese and therefore suffer from fertility problems are often bred slightly younger to counteract this - say from ten weeks or so. A doe will give you the best litters when she is still in her prime, so if you are going to breed from a doe then it is advisable not to leave it too long after 12 weeks before her first breeding.
Bucks
Bucks can breed from the age of five weeks or so and remain fertile until they die. Only one buck should be used per cage when mating up, or the bucks will fight over the does. Each buck can be placed with up to three or four does at a time and should be removed when the does are seen to be pregnant and before they give birth.
Gestation
Pregnancy in mice lasts 19-21 days - in my experience it is most often 21 days.
Litters
Litter size varies with the age of the doe, the variety and particular strain. While mice can have over 20 babies in one litter, the average size is more like 10-12. The young are born without fur and with their eyes and ears closed. The ears will gradually open over the first four days, and the eyes will open between ten and 14 days. Mothers with litters should be kept in solid-sided enclosures to avoid the young escaping. Babies are weaned at four weeks of age and bucks should be separated from their mother and sisters at this point to avoid pregnancies.
Rebreeding
I would recommend that does are given a break of at least three weeks after they have weaned their litter before they are bred again i.e. when their litter is eight weeks old. Condition is key however; some does may regain condition quickly and handle being bred again relatively soon, while some may never quite reach their pre-litter fitness again. Back-to-back breeding is not something I would personally recommend as I feel that mice do better and produce higher quality offspring when they have the time to build back up after the stress of rearing a litter.