Quote Originally Posted by sassy-pants View Post
Between 4 and 6. I always make sure to have the next breeders ready when the old ones are done weaning so I can stay on schedule. Usually one of the females will have a small litter, and that's when I know to replace them. They get sold or fed off when they're done with that litter to make room for the new girls.

so a 12 week cycle times 6 litters puts your rat at 18 months old...Initially, 4 months old they can breed easily...that is 22 months old.

So how many rats have you had come to full cycle and been retired?