I hear heavy rattling in my hen's lungs. She sounds like she has a bad cold and breathes through her mouth. The vet prescribed trimethoprim, an antibiotic that is used to treat Pneumocystis Pneumonia, among other things. She's been on it for a week with NO improvement. I know I'M SUPPOSED TO TREAT FOR 2-3 weeks, but shouldn't I see some improvement? She also prescribed this for my 6 wk old chicks when they were sneezing - to no avail. but it later resolved on it's own. This hen seems perky and is eating well otherwise, and of course she is isolated from the flock. I'm also using VetRx 2-3 times per day orally. Any suggestions? She's bored to death and in my lap most of the time while I work. Thank you.