We live in an area that gets below zero throughout the winter months and found our chickens like the deep little method. It basically consists of turning over the soiled bedding, adding a new layer, and allowing the chicken droppings to decompose on the floor of the coop all winter, while creating heat to keep the coop warm naturally. Then you just clean the whole thing out in the spring and dump it into your compost pile.
A new 6" layer of pine shavings goes down on the bare floor. Starting with the 6" layer of pine shavings on the floor with straw on top, each morning I turn over the top straw so the soiled bedding from the night before ends up on the bottom. I continue doing that each day, adding straw after that as needed to eventually build up to a 12" deep layer. Nothing is removed but rather turned over to expose new straw. (You can also use dry grass clippings, leaves, pine needles, or a combination of bedding types)
Continue in this manner all winter. Early in the spring, sweep the composted litter into a wheelbarrow and toss it into your compost pile. Then scrub down the entire coop, let it dry and replace the bedding with a 6" layer of straw. Through the spring and summer, I remove the soiled straw and it goes into our compost pile for the following spring's garden. I only replace straw as needed to maintain a 6" base. The Deep Litter Method is not appropriate during the warmer months since it does generate quite a bit of heat in the coop which you only want in the winter.
A few caveats before you try The Deep Litter Method: Your coop must have good ventilation (which is very important regardless of whether you use this method or not, to keep the humidity levels in the coop down to prevent frostbite) and if you smell even a hint of ammonia, you need to clean the entire coop out, let it dry then , put down a new layer of pine shavings, then straw and start over. Ammonia fumes can cause eye and sinus irritation in your flock, so it's important that the coop stay fume-free.