I have a silkie mix chick who is 5 weeks old. He has been fine. He's in a cage with 7 tiny serama babies that are the same age. Today I noticed him lying on his side. I got him out and he can't walk. One of his legs is not working right. He is eating and drinking fine. Also, he was vaccinated for mareks at 2 days old. Any ideas? I gave him some poly vi sol today and added electrolytes to the water just in case.