I rescued about 25 chicks about a week ago. They average around 6 wks old. They were in a cage outside in cold weather in the open only a piece of tin on top. Some of them were sneezing with a slight rattle. There is no nasal discharge although a few that have died did have some facial swelling. A few have a small amount of ocular discharge just enough to make eye lids stick. Some them were also underweight for their size. Poop looks normal. All the ones with facial swelling have died. I have read and reread over sympton lists and I am not sure what it could be they have some of several diseases but not all of the symptoms of them. What do think?