Ok, thank you both for your advice. I really only researched about how to hand raise them and how to properly feed and care for them but I guess I got a bit lazy when it came to learning how to introduce new rats and I took someone elses word who breeds them and assumed they knew what they were talking about. Hind sight is 20/20 and I should have looked into it better. Thank you for not bashing me (even though I probably deserved it).

I started with a weaned male because I had read they were able to reproduce at that age so I took that as it was ok to introduce them that small. I wasn't aware they had to be the same size but after the introduction went bad, I started to think maybe that was the reason or maybe he still smelled like Mom because he was so young. These are the first (live) rats I've ever had so I'm still learning. I hadn't thought about them not knowing how to be rats because they were hand raised. They do quite well in their little group and groom and care for each other but I guess it's true that they might not learn everything without having a mentor like themselves to guide them.

I know they are getting older now and about to stop being breeders but I did want to get at least 1 litter out of each girl to carry on with a breeding group before they went back to being strictly pets. It's ok if they don't produce big litters. I really only need a few (just enough to do a very small colony). I put a lot of effort and love into these girls and when they are gone, I would like to have THEIR babies if that makes sense. I know that may sound dumb but they are no longer "just" feeders for me.