We just bought two Light Brahmas that I believe are around a year old. They're at the end or beginning (not sure how to tell) of a molt. I noticed shortly after bringing them home and throwing them in quarantine that one of the hens is coughing/sneezing. Other than that she seems fine. It's been a week and a half. I'm wondering how to tell the difference between a disease and something environmental. My wife threw one of our other hens in with the two quarantined birds (bad behavior and she needed more room) and she coughed a little immediately after being put in the run. This makes me think (hope) it might be environmental. Is there any way to tell? If it is a disease should I assume the other hen is a carrier as well? If I get rid of the sickie do I need to sterilize the run before using it again?