countrygirl4513,
We add Food Grade DE to our flock's layer mash/crumbles. The 5% is the total portion added to the feed. You can mix the two together before storing it for distribution or mix as you go, which ever is easiest for you. (2.5 pounds of Food Grade DE to 50 pounds of feed.)
We also add Food Grade DE to our flock's dust bathing pool and in the nest boxes. Our birds dust bathe in a child's wading pool in the hen house. We put sand, wood shavings and the DE in the pool and mix it together. When I clean out the nest bedding, I sprinkle fresh DE in the bedding.
I don't mix it in any wet feed or treats or in the waterers. Since our birds dust bathe in it, I don't worry about dusting them (like for bugs), but the Food Grade DE can also be used as a bug dust instead of using a chemical dust.
We purchase Food Grade DE at our local farm co-op, and it costs $15 for 50 pounds.
I hope this helps..
regards,
keljonma
if edited, probably for typos....