DE is the ground exoskeletons of microscopic fossilized animals called diatoms, similar to coral. The particles contain very sharp edges that may be viewed under a microscope. The theory is that insects that come in contact with the powder sustain numerous cuts and scratches from which seep bodily fluids. They dry up and die, basically bleeding to death. Many proponents attribute all sorts of powers to that magic dust, claiming it cures everything from parasites to cancer. The theory with internal parasites is that it has the same effect on them as it does crawling insects. Few who share this belief are able to answer what effect the cutting particles have on an animal's digestive tract. Some believe that using it as a dust bath will kill external parasites. It may, but the cutting action also has an affect on the feahter quality. This might be OK for the average backyard flock, but not for those who show, or even just those who prefer to see their birds in attractive healthy plumage. Chinchilla breeders learned this long ago when someone decided to promote DE as a much cheaper alternative to the dust that they use for the animals to keep their coats in condition. The hair follicles were damaged by DE, making many pelts worthless.
I've used it to dust cracks and crevices of a coop to help reduce mites, and in manure piles as a nontoxic maggot killer. I've no proof that it worked, but it was unlikely to harm my birds in those situations. Maybe it helped with your insect problem, even though they were on the walls and the DE was in the bedding. Maybe also you just had a seasonal bloom of a normally short lived species, or maybe the birds finally discovered them and feasted. Either way, they were not mites or lice, which do not jump, and are rarely seen in any numbers away from the hosts.

It does work! I have used it against ants many times. I had ants so bad once that they were coming into the incubator/brooder and killing chicks in the eggs! This stopped after I sprinkled the bottom with DE. I even put it behind the kitchen cupboards when they get bad. It works!

I acciderntally swallowed some DE (in the form of filteraid) in chem class and it gave me a major stomach ache, although it could have been anxiety from the thought of swallowing something with such a long warning lable.

You know, its not too late to sell your add campaign.

There is a diference between food-grade DE and plant-grade. Think the difference is in the finess. My brother is an ag teacher. He went to a hog farm to buy show pigs and this placed used DE for fly control. Mixed it in their feed. Over 350 pigs on this place and NO flies. I have even heard of DE being used for flea powder, too, but it probably was the food-grade, not plant-grade. One of our local alpaca breeders sprinkles it in the animals' dust area to help control mites and ticks.

But if you use beneficial flies, you can't use it, since the BF also lay in poop. I use beneficial flies for the alpaca, but since the new chicken coop is away from them, I plan on using DE for the chicken coop. We have a big fire ant problem and I could just see ants getting into the nests.

I use it to control earwigs around my rabbit hutches. It works like a charm. I'm going to try it under the coop to see if it helps with the flies.

I have heard it is great around your house for preventing bugs in the house. I bought some at the local gardening store in a 2 lb bag. The one thing I don't know is will it harm my toads and tree frogs? It would seem by the nature of it "scratching" the bugs to death it could do the same to the frogs. Does anyone know for sure?

I have a ton of frogs and toads and I surely don't want to kill them.

Most frogs and toads are covered in a bit of mucus, well call it goo. Goo is very hard to put a scratch in as it can just absorb damage and flow back together. However, Is DE effective against slugs and snails?

I heard it is effective against slugs and snails, so that is what has me wonder about the poor frogs.

I use it in the hen house in the dirt bath hole. I've used it for fleas in the dog pen and in the house before vaccuming just in case lol

My feed store sells FOOD GRADE diatomaceous Earth which is not that sold at Home Depot so far (they sell DE for swimming pool filters). Food Grade is reveiwed dozens of time on Internet. I have used it on cats for flea control but I believe that care is needed in the process to you avoid eyes of animals and their chance to have lung irriation when it is airborne as you apply it. It is ineffective as when wet so in my opinion, it is not a long-term solution for fleas being brought into your yard by opposums and foxes, etc. I had hoped it would make a difference with ticks and this last summer deer have been displaced by construction here and deer were often in our yards. One of my cats is ill and appears to have an infection caused by a tick I removed from his body. He had been treated with DE several times so it appears not to kill ticks ?