My flock has somehow been exposed to a respiratory disease, and it's spreading fast. I know I should probably cull the flock, but my fiancé is saying that I can't get anymore if I do. Is there any respiratory disease that doesn't stay with the chicken for life? They're sneezing with foamy eyes, and swollen faces. The only thing I've ruled out is wet pox. I have them on Tylan. Someone please give me some glimmer of hope. My birds are my babies.