FOOD GRADE DE is my favorite method as it works in all life stages and multiple buggers!
  *The dust scratches the outer skeletons of insects and "dries them to death"
  *spread it in the coop:  keep the poo and such dryer, so the poop dries before the larvae can develop (it also kills the mites and lice that are hiding in the bedding!)
   * put some in their favorite dusting areas--in this way, the chickens dust themselves with DE and take care of mites, lice, etc.
  * Feed it to the chickens:  their poo comes out dryer in the first place...and helps with internal parasites while their at it.
I also use Sweet PDZ in the coop (usually when I run out of DE ( I have to order it online, so I can't just go to the store!). (I also put it in the cat litter box and it helps by keeping the amonia smell WAY down--although now I forget to clean it as often cuz I dont smell it).
By the way...if you can't find Sweet PDZ, it's competitor is Stall Dry...both are basically the same.  Usually, feed stores cary one or the other.
Sandra