I have a question. My chicks, now six weeks old sneeze quite often. I see that sneezing is a sign of this disease. Does anyone think my chicks might have been exposed to this disease unbeknownst to me? How can one protect their flock from it? If you buy chicks from a hatchery that does not guarantee against the disease, what can you do? It would be terrible to be keeping hens that may have been exposed to it and not know it. Any suggestions out there on this issue?