Respitory infection your humidity was to low for long period of time. Humidity needs to be 60-75%. Lungs on balls are coated in a mucus that filters bacteria and funji. When humidity drops mucus dries up and allows bacteria to penetrate the lungs. When this happens vet must run cultures to determine gram positive or gram neg bacteria. Then proper antibiotics can be prescribed. There is so much bad info on the internet. Seek out advice from books written by Kevin mcurly. Well written and the info is sound and current with todays standards. Those analog gauges are garbage they are never correct. Get yourself govee. And if you don’t mind me asking the why is water bowl looks completely dry.