I have some Lav Orp, BCM, and Golden Cuckoo marans chicks in a pen off the ground. They are about 8-10 weeks old if not older. They dont look good. Some are walk bent over like they cant stand up and a couple are standing there like a young baby fighting sleep. I watched one close eyes and open and then close again and almost fall over. They were even drinking water with their eyes closed. What is this and why is it happening. I dont wanna lose any, got to much invested in them. Plz Help