I have 11 chicks, about 3-4 weeks and have never had chickens before. One my chicks is about 3 times the size of the others, and I'm noticing him not walking around much and lying down to eat. Someone told me that they can get so over weight that their legs crumple. Is this true, and what do I do about it? I can limit his food, but how much should I give him, how many times a day? He really is huge.