Humming chicken ?sick?

Hey Permies, I have a chicken that just started making a "huh/hmm" sound every time she exhales. If it's a disease, should she be culled? I've heard that viruses stay wth them for life. I have a small flock so I'm reluctant to lose a young layer, but if all the others are at risk then it's worth it. She's 4 months old and appeared to be healthy. No foamy eyes or watery sinuses yet. I just noticed her strange exhaling sound and quickly put her in quarantine.
It just rained buckets after a dry spell so the air is humid (Florida) Any suggestions? Thanks, Huxley

Hi Huxley,

If she appears to be gasping for breath too, consider gape worms. They were very bad in this area last spring after a wet spell and are spread by birds. After losing 3 pullets with no real warning, I opted to treat the whole flock.