I use large flake chips in the covered run, and use chopped hemp in the nestbox and currently for the brooder too. I haven’t tried straw.My ladies only go in the coop to sleep or lay, even during the nastiest weather. They will get up late/go to bed early, but otherwise they are out somewhere. In the summer i use sand and some used coffee grounds. My coop is elevated too, about 3 feet off the ground. My biggest issues are cushioning their jump from the roost (my ladies are all 5+ yrs) and some insulating come winter. The run is dirt and only partially fenced, they mostly just dust bathe there.
The hemp is expensive relative to pine flakes but it’s really great. It’s very good at absorbing moisture, and the little chopped bits cling to poop so it’s easy to remove without taking a lot out. In the nestbox I’ve got anywhere from two to five inches going, the deeper the better. It will compact together to a degree when they walk on it, so it is nice for making a hole to fit in how they like, and it’s firm underfoot even though the nestbox has a smooth plastic floor, so what they make keeps it’s shape. Yet it fluffs really nicely too, is insulating, and I appreciate that skinny Butters, with her oh-so-prominent keel bone, can snuggle down in it and (I think) be comfortable.