I've had a 1.2 trio of VIRGIN rats in my care (housed together for breeding purposes) for between 3-4 weeks. Everyone has gotten along fine until the last few days. One of my females likes to pick on the other one and they get into some loud scuffles (but no injuries noted on either). One of the females is starting to look a little pudgy (she is the instigator of the scuffles). Could it be a pregnancy related aggression? This is my first venture into rat breeding and I have a whopping 0 litters under my belt so any help is appreciated. I just don't want any of them to get hurt.