Quote Originally Posted by Jay_Bunny View Post
It was always recommended to me to wait until they were 12 weeks old. Is there a reason for this? I retire after 6 litters. Of course that is my rule but I have never had a breeder colony long enough for that.
Well those are guidelines but I pretty much go my my own guidelines based on what work with my colony.

I have been breeding rats and mice for a few years and have try various thing and 8 to 10 weeks with my colony seems to work perfectly, I have tried younger but they tend to have smaller litters and more prone to cannibalism.

At 8/10 week they average 12 to 16 babies even as first timer and they never eat their first litter.

I guess I could wait a little more but let's face it the breeding lifespan of mice is already very short so 8 to 10 is what I go by.