I went to get feeders today and asked for some extra mice to be used as breeders. Once I got them home, I weighed them and did my best to sex them. All mice I purchased are under 20g, the biggest being a 19g male. The smallest is a 11g female. Two are colored and 6 are white. I believe I have four males and four females. I weighed one of my females who was going to be a breeder but she never produced anything and she weighs 40g.

What do you think I should do regarding the small mice. I was thinking of taking my two empty tanks (20L) and seperating the sexes and monitor their weights as they grow. Even the ones I bought for feeders need to put on more weight before I'm going to feed them to my snakes.

Since I don't know the ages of the mice and only their weights, at what weight would you consider it to be ok to begin breeding. They all look to be 4-5 weeks old, but again, I'm not sure. So lets just talk weights here for a bit. What weight do you consider good for a female breeder mouse?