Hello.. I have a couple of chickens that are having respiratory issues. I have decided to treat I am aware that this may come back & is not a cure by any means. I have given the Tylan 50 injectable orally for 5 days 1/2ml for salmon favorelle & 1/4ml for silkie it has not cleared up. Symptoms of silkie are sneezing, gurgling, weird coughing like sounds almost like a dogs squeaky toy. She did have some discharge from eyes before and a little from nose. Salmon has had all the same symptoms except the squeaky toy noise. They seemed to get a little bit better after the Tylan but not totally. Wanted to try something else but the only things I have access to are duramycin which I thought was pretty weak & sulfadimethoxine or llncomycin-stectinomycin?? Not sure which to use? Thanks so much for taking the time to help me.