Quote Originally Posted by mues155 View Post
Your probably ok to mix sexes in tubs until the testicles drop in the males which is probably give or take 2 months...It is POSSIBLE for does to be bred well under 4 months old. Which is horribly dangerous for a doe. Just because they CAN breed doesnt mean they SHOULD.
I wouldnt breed a doe until AT LEAST 6 months old. They need time for their pelic bones to fuse and support burthing kittens.
If your rats are weaned and can be properly sexed I would seperate them. They will get plenty of comfort with their same sex siblings. But thats just my opinion!
I'm pretty sure pelvic fusion in rats is a myth, and originally was used as a reason to breed rats young, not old. I've bred tons of rats under 4 months, several as young as 6 weeks. The only really bad effect I've noticed is they are often terrible mothers.