You might look into the deep litter method. I'm using this in both of my coops and it works nicely. The premise is you add several inches of litter (I use pine shavings), and the chickens scratch around and stir their own litter, helping to keep the odor and everything under control. I also stir it with a spade or shovel at least a couple times a week to fluff it back up, and top dress with some fresh shavings once a week or so. The poop and shavings can compost a bit at the bottom, helping to generate some heat in the winter.
If the system is working well, you should only have to do a full litter changing once a season, but I always promptly remove any damp or wet shavings and replace with fresh to keep mold and bugs down. You can also spread a layer of food grade diatomacious earth (DE) on top to control moisture and odor.