Various sources and textures will work. Using the different textures can help increase pore space and keep it from packing down. In my case, I have pine needles, leaves, grass clippings (not so much at the moment), hay, those little round pokey balls from the tree in my run, pine cones, leftover scraps they don't eat like corn cobs and various peels, and so on. You want variety.
My first winter I tried just straw to keep their feet down. It formed wet, stinky mats that I then had to laboriously transfer to the burn pile. The hay seems to be much better at fluffing itself back up in a sunny day.
My first winter I tried just straw to keep their feet down. It formed wet, stinky mats that I then had to laboriously transfer to the burn pile. The hay seems to be much better at fluffing itself back up in a sunny day.