Wow - You seem to have covered all of the bases! Do you dust the chickens themselves with the DE and Sevin or just put it in the bedding, etc.? The Tractor Supply near me has the Adams spray - do you just liberally spray them down with it, especially near their vents and if so, does it seem to irritate the vent area? Thanks again for your answers and insight!
I use DE, Sevin dust and Adams fleas and tick spray. I am not real sure about the Sevin dust either, I won't eat the eggs when I use the Sevin dust. I have heard most people just use DE and it works out great for them. I also know someone that uses Frontline spray but you can't eat the eggs either. I am confused about all this too! I hope you get some answers. 
I do the coops and the birds, I am still a little afraid of the DE, I know I'm not supposed to breathe it in, but knowing me, just because I'm not supposed to, I will!!! I usually have my husband put the DE down for me. He wears a mask and he has been just fine. He gets mad at me when I ask him to do it, he says "what you trying to kill me off! " LOL. The Sevin and the Adams, no problems I do the coops and the birds.
Shake and bake!! 
I'm gonna try that, it sounds like a good idea! I dunno about the bag though, I would think the chicken would shred a plastic bag while it was attempting escape!
