I just got one rat a few days ago. I knew ahead of time that I should get one of his brothers so he'd have someone to hang out with, but I didn't have the money that day. I read up on introducing new rats to the cage, and found that you have to do it slowly... But I am planning on getting a rat from the same place, who were my current rat's littermates. Do you think they will still have the same adjustment issues since they've lived together all their lives, or will it run more smoothly? I don't have the extra space to keep the new rat if I have to acclimate him to my current one.