possible coryza outbreak in my flock
Welcome to BYC. MG and coryza both can cause swelling around the eye, and you can't really tell which one for sure without blood or nasal testing. Your state vet also could perform a necropsy to test for it. Coryza generally causes a bad odor around the face. Since both are chronic diseases, they can come back, and sometimes are complicated by secondary infections such as E.coli. Most sick chickens won't drink enough water to get medicated with drugs in the water. Many give Tylan 50 injectable orally or by injection to treat MG.Coryza can be treated with a combo of Tylan 50 and Sulfadimethoxine or Sulmet. Quarantine won't prevent these chickens from being carriers. I would probably call the state vet to check on testing or a necrospy--here is a link for that:
I gave tylan 200 injections in breast for 2 days, 1 cc for older birds and half that for younger, as well as electrolytes in water for a week. They all slowly regained health. Keeping the coop clean and disinfected, spraying vet rx often and applying it onto birds necks & under wings seemed to help ALOT.