My flock recently came down (in December) with a gurgling and raling respiratory issue, which started in a humid poorly ventilated coop. I got a bird necropsied about a month after it started, when only a few different ones each night would gurgle (like it was quickly spreading through them). Everything is negative. The question is, is it something that just didn't show on the tests? Or is it something minor that will go away? I don't know whether to depopulate and start over or start hatching again and see what happens. ANY suggestions?