For the past few weeks, our bantam frizzled Cochin hen has had a stuffy nose and pretty rattly breathing. She also seems tired. This is especially concerning to me because she is almost 6 years old. We gave her some antibiotics in her water for a week, but that didn't get rid of it all the way though it did help. I was wondering what we should do to get her healthy again. Is there a medicine or something else we could give her? Thank you.