We noticed today that my roughly five-month old cockerel isn't breathing well. It gets extremely hot and humid where we live, so all the chickens pant all the time. So it might have taken us longer to notice than usual. His panting didn't alarm us. What did alarm us is a gurgle sound when he breaths, like there is fluid in his lungs or something. Any ideas what this is (possible respiratory infection??) and what to do to treat it?