I'm currently treating a hen for a possible resp. infection with Tylan and doxy, but I'm not sure if it could be gape worm or not---can I do all of this at once? She has been sneezing and coughing, shaking her head, and gasping when distressed. No nasal discharge or eye swelling/discharge. I know gapeworm is supposed to be relatively rare---is it present in certain areas of the country more than others? I am in Maine. Thanks!