not sure what is happening at all. Hatched 15 baby chicks, and at 12 weeks I only now have 4 left. 1 died of an injury at only a couple of weeks old, but the rest have died suddenly at different times since then. Have been putting vitamin powder in their water on and off, along with apple cider vinegar, When symptoms arise, they are sudden. One may be sluggish and off balance, then within a day, gone. No noticeable wheezing or anything like that. Poop is normal. This morning one of my barred rocks was dead, and one of the others face and beak was completely white and her eyes are half open. I moved her to a separate pen immediately, but I'm at a loss. I had one male that suddenly started getting growths on his eyes, and one eye was taken over by the growths. I put him in the separate pen, but a raccoon broke in and got him. None of the others had anything like that. The coop is a 4ft by 16 foot run on dirt, and we built a sand box for dust bathing, and they have a protected sleeping area. Plenty of food and water, sunshine and shade. Any ideas?