I noticed yesterday my black copper marans making a rattling sound when he was breathing. He also had a crust around his nostrils. He's always (he's ~4 mo old now, I've had him for 2 mo) had a bit of a runny nose, so I didn't think too much of it. Tonight when I went out to tuck everybody in I noticed a weird sound coming from the coop. My youngest bird (an EE) had her head in the air, beak open, rasping for breath and occasionally sneezing. The marans seems slightly better than yesterday, and when I went out to check on them a 1/2 hour later, my EE seemed fine. No rasping. No wheezing. She did sneeze again, though. I don't know what's going on. It's pretty smokey here (wildfires), but I don't know if that bothers chickens. It's bad enough that I'm a bit congested and bothered by it, but I haven't even dipped into my allergy meds yet (I'll have to if it stays this smokey tomorrow), so I don't know if maybe a couple of the birds are sensitive to it, or if they're getting some respiratory thing. I will NOT take them to the vet (no $), but I would be crushed if I lost any birds.