I have 8 Langshan and 4 maran 2 1/2 month old flock. We just moved them outside to their coop and noticed one Langshan's neck seems floppy. It can lift it up and it seems to flop from side to side and also turns sort of upside down. Otherwise it is ok, walks and chirps and the rest are fine. Any ideas what could be wrong? I raised chickens and turkeys for years and never saw anything like this. Help