Is this the one you are talking about?
http://www.wolfcreekranch.net/defaq.htm
I have used DE for 4 years now.
I mix it in my chicken feed at 5% and put it in their coop . I've not had mites or flies at all.
My dogs get it in their food also and so do I . None of us have had worms or mite's either.
I use it for myself as more of a colon cleanser. I lost my dad to colon cancer and decided to try this. I will say it definitely makes me feel less sluggish than if I don't use it.
In the garden I usually apply in a wet solution with a sprayer, I just find that it sticks better and there isnt the dust issue then. It's been real effective for aphids and in my veggie garden. I have not noticed decreased earthworms at all as I dig them up for fishing and for
my chickens at least once or twice a month. My straw from my coop goes into a compost pile and that is where I find my earthworms. I usually avoid spraying during pollination so that bees arent affected and for most plants I spray around the plant on the ground.. not on the leaves except for roses, tomatoes and peppers as those seem to attract the undesirable bugs the most in my garden. I have used it with much success for ants in my windowsills and under my sink as that is where they seem to come in to my house.
My feedstore sells it in 50# bags or in the bins where you can buy whatever amount you want. It's also sold here in organic gardening stores.
I dont use it with chicks but wait until they are in the coop so I'd say 6 weeks is the earliest they get it.
Only negative I've encountered is the dust but since I started the wet application I havent noticed. In the chicken coop I keep it as close to the ground as possible so it hasnt been an issue. I guess the other negative is that it's hard to find sometimes as it always sells out around here. I usually just order a 50# bag from the feedstore when I'm getting low.. but it lasts a LONG time.
Nancy