A few months ago I adopted two RIR from a feed store that has since closed down (by animal control). There were a number of problems with them, but over a few months time, they've gotten back to full health. Now, one of them has started sneezing. I assumed it was allergies since one of my younger hens had been seen sneezing the day before and since then has stopped. The problem is that today she isn't acting like herself. She sounds stuffed up when she breathes, a little gargling sound. She's generally a social bird and aggressive when it comes to treats (pushing her way to the bowl, or stealing them from other birds). Today we cut up fruit and tossed it out to them. She walked over to us, stopping about 6 feet away and stood there. She made no effort to eat and even when the fruit was placed directly in front of her, she didn't touch it. I didn't think too much of it until I locked them up for the night. The two RIR perch on saw horses and only go to the coop when I physically put them in. Her sister was perched, but I couldn't find her. I then heard a strange gargling noise (this was when I realized she was doing it) and noticed her on the ground. She doesn't seem to have the strength to join her sister on the perch. Is this a respiratory issue? Could it be allergies?