Its going to be more than one thing that get you what your looking for. Keep it dry, clean and use what you have to. Sweet PDZ, poop boards, pine shavings. Regular cleaning, permethrin 13.3% in bug sprayer, composting the right way, fly traps... If you do all of that half right most of the time it will work. Do just some of that and it will have to be done right all the time.
Poop boads cleaned once a week and 50% or better Sweet PDZ used on them.
Pine flake shaving on floor of covered coop/run. Add some every month or more. Change out twice a year. (every forth month for me)
Rake, fill holes, straighten up once a week. Once month add new shavings to nest box and floor. I put all the nest box shavings on the floor and use new. Ever other month I spray everything with permethrin. When the nest box shavings gets changed, I spray the empty nest, all the wood. Undersides of poop boards, roost boards, floor of coop, run, six feet around the outside of coop and run and the compost pile. Broad cast some sweet PDZ on the ground after raking.
Compost with the right stuff , make three piles.
1) Dry brown leafs and clippings
2) green fresh grass clippings and plants
3) chicken poop and cover with as much from piles one and two.
No flies, no smells no mess. Get it in routine and its not that time consuming.