Deep litter is a method of keeping your coop/hen house.
It is 6-8-10 inches of pine shavings. It keeps the hen house cooler, and cleaner. There are several forums/posts about it on this website. I use it in my hen house. I also sprinkle a little DE and Stall Dry on it about every 2 weeks, to keep the smell/flies down.
I also use some 5 % Sevin Dust to keep it free of mites/flies/other pests.
Look up subjects of interest on the Search section of this website. It has lots of good information and you don't have to wait for an answering post.