Has he been to his doctor about it? Could he possibly have bronchitis, OR mycoplasma? People get mycoplasma too. The exposure can be a result of going to the feed store, and someone else carried it in. It doesn't necessarily have to be from your own chickens. A prescription of Doxycycline clears it up. IF/When that has been checked out, but he's still having trouble, let them do further testing, especially an X-ray. I was coughing, short of breath, getting weaker, and weaker, etc. I was first treated like it was a bronchitis type infection, because I had a bout with bronchitis. The bronchitis sort of cleared up, but I continued having trouble. The doctor kept prescribing antibiotics, and prednisone. Eventually, when that didn't help, it took an X-ray to show that there wasn't a problem with the lungs themselves, but the pleural space (adjoining the lung) that was the problem. No, it wasn't cancer there. The bronchitis had inflamed the pleural space, and when I got over it, for whatever reason, the inflammation didn't resolve itself like it should have. It can become life threatening, so don't wait around to get it checked out.