nasal

I have four free range chickens. My oldest girl (a year old). Started sneezing randomly a few times and she looks like she is molting. So we isolated her in a spare pen we had. I live in the Mojave desert and most of my yard is dirt and dried weeds. Is this a simple case of nasal irritation...

I have an 8 month old bantam hen that has an ongoing nasal congestion but is otherwise healthy and energetic. Eats well, drinks, runs, plays, sleeps, etc. The congestion is yellow, hard, and smelly. An older hen of ours would every once in a while have the same issue (like once every year or two...