I have alot of chickens and ducks and geese and turkeys 80+ birds But I also do meat rotations. I have never had this problem before or anything but I got 33 Cornish X and 3 Buff orpingtons and 3 Pekin ducks in my order this month they were all fine until about week 2 they started sneezing but it was only the cornish birds. Everyone else was fine after being together for 2 weeks with the sneezing but i finally separated the ducks and chick's from the cornish just to be safe but there just fine nor sneezing or anything like I said just the cornish ones and all my other birds are perfectly fine its just this weird batch of cornish there not puffy eyed there not lethargic or runny nose or anything they been like this for 4 weeks now and are just fine eating and running around and everything I even changed pine shavings to hay for bedding even gave them some electrolytes packs. Even bleached and did a deep clean of the brooder for a possible mold and layed down DE in case mites were gettin in there nostrils I have Litterally searched and looked and did everything. There not in any pain there happy and what not and I haven't lost any of em. So I just wonder if this could be because of genetics or something they got from the mother I'm just out of options now and just curious of what could be going on.