My 2 month old kitten, Taco, has some weird things happening to the muscles in his legs. When he is standing still, his hind legs shake a little. When he is relaxing or sleeping, the muscles in his front and hind legs seem to have little spasms. It looks like he's cold, but the house is always warm so I know it couldn't be that. It doesn't seem to bother him one bit, he still runs around like a little maniac. In fact, he is the most hyper kitten out of the litter and he's the runt. I was wondernig if it could just mean that his muscles are under developed, since he only seems to have the spasms after running or moving around a lot. What do you guys say?