I have two boys that only have about a 5-month difference in age. When I first introduced the younger one to the older everything was fine and they were perfectly happy with each other. As the younger rat has grown up they have started to have more and more issues with each other. Eventually, I had to separate them, because they would fight to the point of drawing blood. At first, I just closed off the levels in my ferret nation (which have has hardware cloth around it) they we're fine for months. Every once and while the younger one would climb up and they would just sniff each other and I assume communicate in a way I don't understand. Recently though they have started pulling out each other's fur. Being scared that toe biting is next I've put the younger one in an separate cage all together. This is my first pair of boys and I am just at my witts end on how to help them get along. They aren't aggressive with anyone else, they just seem to hate each other. HELP!