When I went into my coop last night I heard some rattly snoring sounds which I hadn't heard before. This morning, my three Wyandottes have rattly breathing, two hens and a rooster. What would explain this? They don't have any other symptoms so far that I can see. No watery discharge or mucous, their eyes look normal. The one hen has been broody for several weeks and still is, the other hen has been active and just laid an egg and then went outside, and the rooster seems his normal self. Besides the three Wyandottes, I have orpingtons, wheaten marans and easter eggers, none of which are showing any signs or symptoms so far. Any idea what would explain the sudden onset rattly respirations, and the fact that only the Wyandottes have it (so far)? My chickens are in a clean coop, well ventilated, outside daily unless it's really wet out there. We've had a lot of rain here (we're in BC, Canada), but also a lot of decent days, not too cold, and they have been outside most days. They get clean water regularly, usually with ACV but I had not been adding that lately. I'll start that again, as well as extra vitamins, and will give the three affected chickens colloidal silver. Not sure if I can mix the silver with the ACV in the water, am waiting for a call back from a pharmacy where they deal with veterinary issues and natural approaches. They don't diagnose, however, but will advise once I have an idea what I'm dealing with. So if there is anyone who has some experience with this I'd really appreciate hearing from you. Thanks!