I am trying to introduce 3 4 month old rats to my current 4 year old. When they are in a neutral area like a tub they all get along fine and sleep together, however in the cage its a different story. My 4 year old girl watson will stiffen up with the others approach her and will let them walk all over her, sometimes the bigger girl of the 3 will fight with watson, and now she's hiding in the bottom half of the cage and was down there all night (this was the first night i had them all together in the cage). I found small scratches along her side that I'm assuming is from peaches, the bigger rat that picks on her whenever they get close together. I don't know what to do, i feel bad because to me it feels like watson is loosing her home to invaders now.