I'm also dealing with a mild form of MG, I think! Just occasional sneezing... My girls free range and picked it up from wild birds I'm sure of.. ... It stinks bc it's my first time owning chickens... But we live in the country and we have wild birds, mice ect..... I could cull and start over but I would still have the same issues again.... So I choose to let them live happy in the sunshine too.... I never dreamed I would become so attached!! I don't think antibotics really have helped, I just try to keep their immune system up with vitamins.