Sweet pdz isn't meant to be flooring. it's just a supplement to the shavings. if you did put it down the way I told you too, I think you'll be really surprised how good it performs as a flooring method . if you put in 4 inches worth of shavings... okay, those birds are going to dig down but they're not going to stir up a whole lot of DE or anything like that.
but the de is going to sit on the very bottom.
the bugs and stuff are going to crawl to the very bottom . they are going to get the de on their exoskeletons, it will scratch those exoskeletons and they're going to die of dehydration way down deep underneath . the sweet pdz on top of the DE is going to help keep your floor dry . you're not going to have a wet floor in your Coop. it's also going to get rid of the ammonia . the 4-inch of chips on top of hard wood shavings , they're going to keep it nice and soft for the birds and you're going to be fine.
but the sweet pdz isn't meant to be a flooring. it's meant to be a supplement underneath the flooring to cut down on moisture and ammonia . I think you're going to find it with four inches of shavings the birds are going to mix the poop into the shavings, you're not going to have anything to scoop . it's going to gradually get matted down a little bit and then just add another 2 inches of chips on top of it.
if you go to add for two more inches of chips on top of your regular flooring , you do not need to add more sweet pdz and DE. If you desire, you can sprinkle some pdz on top of the flooring you already have before you add the two inches of new hardwood shavings but there's no need for more DE.
Best ,
Karen
P.S. I never had roosts in my Coop my Light Sussex just snuggled down into the chips in the winter. I made sure it was 6 inched worth of chips in the winter and they would just snuggle down into the chips and be very happy.