I have a number of new chickens that are about 5 months old. They are now mixed with my older chickens and seem to be getting along well, except they choose to stay out in the run at night on a perch, instead of perch on the roost inside the coop with the older chickens. I'm expecting that to change as the nights begin to get colder here in MN. My new chickens seem to have some type of disease that I can't pinpoint. It progresses as follows: First they seem to slow down, then one eye swells shut, followed by the other eye, and then death - All within a couple days. My coop & run are relatively clean, being I work from home so I can clean it every day. It's about time for me to change out the pine shavings, but I have DE mixed in with it, and turn it every day to keep it as fresh as posasible. I just started putting Apple Cider Vinegar in their water, but had not been doing that through the summer. Is it possibly some type of respiratory infection? I haven't done any necropsy, so I don't know (and I am not experienced at necropsies). I've lost three out of nine new chickens and don't want to lose any more. Any ideas? ANY HELP IS GREATLY APPRECIATED! Thanks.