Help chicken stopped using his foot!!!
Frostbite is very common this month of the year, and if chickens step in any water during freezing temperatures there is always a chance of it. The toes will become discolored and then will shrivel up and fall off eventually. Pictures would help. Here are some pictures of frostbite and some links to read:
Is there any thin string wrapped around his toes or anything, cutting off circulation? I can't think of what else it could be at the moment.
Also, are his toes curled or just hanging limp?
Wish I could be more of help.