well, for one thing, I noticed a musty smell on some of my straw. then, yes, I did a process of elimination on the other duck that had it, and I gave her dewormer in case it was gapeworm, and I gave her antibiotics in case it was something that needed that, (but she got worse) and I finally started treating her for the aspergillosis and she got well. So the one runner duck that had it really bad was coughing a lot. but the other one just had no voice at all when I added the voice duck to the treatment plan her voice came back. It was wonderful.