I have one hen who has been having the "sniffles" for a couple months now. I noticed that she has been breathing through her mouth and I hear her sneezing occasionally. I have noticed no nasal discharge and no change in behavior. She is the only bird out of my flock showing any symptoms. I would like to help in her recovery, but am unsure which of the many respiratory aliments she may suffer from. Any advise would be greatly appreciated!