Okay, so I tried to get PDZ at the feed store, but all they had was Stall-Dri and it was twice as expensive as the same quantity of feed... I just couldn't do it! lol So I decided to try the old stand-by: Baking soda. I hesitated, because no one on here or in any of my reading seemed clear on whether it was safe for ducks, but I decided to take a chance because it's so very innocuous for humans & goats (in fact, it's a tonic against bloat in goats), and because I know it's present in a lot of the breads people use for treats for ducks. I realize that doesn't necessarily mean it won't hurt them if ingested directly, but I figure since all my research didn't produce an answer, the only way to find out was to try a little. So I put a tiny bit on top of their bedding this morning, and watched for a bit. They picked at it, but quickly discovered it wasn't yummy and mostly left it alone. So then I poured more in, so there's a fine covering over the whole floor (quickly ground in by their walking, and washed in by all the water everywhere, of course). It's now 12 hours later and the brooder doesn't stink!! I use baking soda for SO many things around the house. It's so cheap and useful and non-toxic. And now I have a new use! Yay! I'm curious whether anyone else has tried baking soda? If you have or do, I'd like to hear about it--I'd hesitate to actually recommend it to anyone until there's a larger body of evidence beyond my one brooder of ten ducklings. Thanks!