I don't have a dirt floor, so I am not in the same predicament, but when I used straw, I hated it. It became a huge matted mess, in short order, and is said to be the perfect place for little unwanted pests to reside in. The straw would poke at the chickens and myself when I would walk across the floor. I started using pine shavings, and what a change for the better! The chickens are cozy and comfy, and burrow themselves in just to feel good like they would in their dust bath. They love it. When it was _50 F. out, (even though we have an insulated floor, the floor still gets chilly given those nasty temperatures) so I put in 6 inches of pine shavings, and they were toasty warm.