I had two intact males together for 2 years. One just passed and the second was devastated. I decided to get him a big family to cheer him up. First I brought home two unaltered boys about 4 months old. They are not related. Introductions went swimmingly. Sam , my old man, was delighted. When I saw that everything was going good I decided to get a baby about 6 weeks old that I feel in love with the first moment I met him. Sam is ecstatic. He’s 5 times bigger than the baby but wants to snuggle up to him constantly. One of the 4 month old boys loves to snuggle the two of them. One big happy rat pile, except for one of the 4 month old boys. He stays away from the others. I’ve even seen Sam try to snuggle up and the loner just walks away. He doesn’t seem to be brooding or kicked out, he just keeps his distance from everyone. I haven’t witnessed any fighting or territorial disputes. Is the lone rat ok? I’ve had rats in the past but all have always bonded. I’ve never seen this behavior.