I have a two year old male rat named Nico, who seems to be acting a little weird lately. He is starting to lose the function of his hind legs a little, so he didn't really climb from my lap to my shoulder anymore, but lately, he has. Also, he seems desperate for free time. We are sort of halfway through introducing him to another younger male rat (Remy), at the stage where you put the two cages next to each other, and whenever we do this he seems really really desperate to come out- he will ignore food and try to escape his cage. And, his tail seems to be drying up a little. It has become sort of scaly- ish and some of the scales are peeling at the edges. His fur is ruffled and stands up on it's ends a little. He had a little respiratory infection a about a week ago, but it's all cleared up. I thin that the hyper rat part may be because of the new rat, but is the tail a sign of sickness? Please help!