Unfortunately, I had to do a lot of research on chicken diseases last winter. A lot of chicken ailments and diseases have similar symptoms when they get to a certain point, so it can be really confusing. If I were you I'd start them on antibiotics, for one thing, unless you're going to just cull them. I do know that bubbly eyes with discharge, diarhea, and sneezing and weird breathing can also be signs of Avian TB in it's later stages. It could also be ILT in it's advanced stages; at least that's curable with a vaccine and antibiotics a lot of times. I don't have first hand experience with Coryza but I know the symptoms are similar there, too. Whether or not you cull them or one dies on it's own, it is probably worthwhile to have a necropsy done, so you know how to treat the others if you have to.
