I haven't read theu all the posts but saw the word Coryza and thoguth I would post this. I have had PERSONAL experience with Coryza and found this sight most helpful. This college is KNWON for its animal and Vet schools, I also attended this college.
http://msucares.com/poultry/diseases/index.html
http://msucares.com/poultry/diseases/index.html