crested gecko,

Question
my crested gecko is about 6 months old. he is shedding alot latley and is the shedding skin is appearing to be whiter than usual. he has not eaten in a few days. & also when he walks he is lifting his back legs up. it seems he is walking a bit funny. he also looks thinner.

Answer
Shedding is a normal process when reptiles are growing which I am sure you know already.  Outside of that I would venture to say that the whiter skin could be a humidity thing which I really wouldn't worry about at this time.  Typically when reptiles shed they are not interested in food so that actually makes sense that the Gecko has backed off of feeding.  The walking thing though seems odd to me as well.  I would look closely at the Gecko and make sure this is not being caused by skin sticking to the toes or leg area which might be causing him to walk funny.  Barring that, I would watch him closely for a couple more days and if he's still walking funny I would suggest a vet visit so that you can identify any significant problem before it gets serious.