I have a few adorable 8 month olds that I have over-winterized. They are all nice and chubby and just precious. Today I noticed one of the boys tail has thinned out. When he climbed down his tree I noticed the thin bone in the back of his tail. I did see a few tail hairs cleaning out the cage one week ago,and I just poo pooed it. Its the entire tail that is thinning out. What could be the cause of this. His Diet is perfect. Still drinks milk as well....