My favorite use for DE is adding it to my chicken's feed (just a little dusting from a sifter into an ice cream pail of feed, and swish it around). I've read it prevents intestinal worms and have never seen any worms in their poo (I use no other treatments) so I think it works. But even better than that, the DE passes through into their poo and flies will NOT land on it. I have absolutely NO FLIES in/around my coop and run, with 10 chickens in an 8' X 16' run. I similarly dust the litter in their coop and it seems to keep things very dry in there, even through the long winter of confinement. I dust a little into their nest boxes to discourage mites. Yes, it is dusty in there, but I have had chickens for 5 years and have never had one develop any respiratory problems. I am careful to wear a damp bandana around my face when I shovel it out in the spring. I do compost the litter so I suppose it is finding its way into my compost, but since it is in the SOIL and not on the blossoms, I don't worry about harming beneficials. I have read that it has no effect on earthworms, and in such small proportions, I can't imagine I will ever get enough of it into my garden soil to create a problem.