Yes it probably is coryza. I've ordered some tylosine to treat the whole flock.
What I don't get is why cull the whole flock? I was thinking of doing it but then I realised, it will cost me a lot more to replace them than it will cost me on anti biotics.
And so what if they are "carriers" once they are cured? The chances are some other bird I buy might be a carrier. So what? Most birds probably are carriers of some disease or another. When they have been through the illness once, their immune system is generally a lot stronger against the particular disease. Most animals as well as humans are probably carriers of some bacteria or another. If a new bird is introduced to the flock and catches the disease, I'll have some antibiotics to help it see through the disease, and after the first time it will be fine. If the chickens egg laying rate is not noticeably affected, and their meat is fine to eat, and they are acting happily like normal chickens, then what does it matter if they are "carriers"?
Edited by brummie - 10/26/13 at 9:23am