We just moved our silkies outside, and today one of them started falling over and is acting very lethargic. He also feels extremely light- which is odd considering I handled them both yesterday. He can't seem to stand on one of his legs. Is this Marek's? I was told Marek's wasn't a problem in our area. Is there something else that could be wrong with him? He's about 2 months old, btw. We had them outside in a tractor yesterday and they did good but I noticed him flopped over in his coop this afternoon.