Thank you Eggcessive,
The coop is really quite clean and we run a fan to circulate air (and have ventilation on top of the coop). I'm wondering perhaps the new duck poop or the water getting a bit of algae? We change out the water if it starts looking a bit scummy...
Could the hen who was...
My beautiful Rooster has had symmetrical black (sometimes moist with blood) scabs on both sides of his comb near his nostrils for at least a month now. They have not seemed to cause any problems. But he has slowly been developing a wheeze - today it's really bad. Then I noticed he has more marks...