It first started with just a few, which I separated, but I guess it was too late, as it started spreading in the main coop. Some of them do have a discharge from the nose. The chickens that have it have a smell that's not too strong. I read that coryza has a horrible smell, but I can't say this smell is overwhelming. I have to take a whiff of each chicken in order to smell it. I have tried to add vinegar in their water, then a couple drops of bleach as a disinfectant, and recently, 15 drops of GSE per gallon of water. Nothing seems to be helping. I would love to avoid using antibiotics, but I guess there's no other way. Can anyone give me any advice for this situation? What to give and where to get it? I also read somewhere that dust in the air could cause this. The main coop has straw in it, which a neighbor also uses but doesn't have this problem. Plus, I used wood shavings for the chickens that I initially separated, and their sneezing didn't stop. I would appreciate all the advice I could get. Thanks. Edit: forgot to mention: besides the sneezing, they're behaving just find. Eating, drinking, scratching, etc.