I have used Sweet PDZ all summer since my chicks graduated to the coop. No smell what-so-ever! GREAT STUFF, right? Not so fast! On occasion I sneak out there at night and pick a girl off the roost and snuggle her and put her back and if she flaps a bit the stuff will fill the air so I ventilate by swaying the door back and forth to pull in fresh air and suck that out. I had NO idea to the extent that it hangs in the air until the other night while I was out I heard a bustle in the coop for a sec so I went to see what the fuss was up, opened the door and there was a cloud of it hanging in the air! Not settling on it's own, but just a thick cloud hanging for them to breathe in, so I waited and waited aaaaaaaand waited, and lo and behold it doesn't settle easily let me tell ya.Well I had previously done some reading on chicken lungs and respiratory infections because they have developed a blackening in the nostrils and slight darkening of the beak and some beak crustiness near their little nostrils as well. And you do NOT want to mess with something in the air as their lungs and not designed like ours at all and they can't handle this stuff in the air at all from what I had read. So long story short, I removed it and their nostrils are finally improving, in 2 days I might ad! Ok so tiny poo smell when i scoop in the AM but tha'ts it. I lined my poo board with linolium and feeling much safer now. Not to mention that I actually am liking that I can see what teir poop is all about as opposed to the white coated dried up poo the sweet pdz turned it into so that I couldn't inspect it for anything that might occur in their systems. So there you have it, my opinion on the powder puff called sweet PDZ