You can go several ways and this time of year lots of people use a combo. In the run you can use, leaves are great and free, hay, clipped grass, chipped bark from MOST trees- not straw--those hollow tubes are great for mites and lice to hide in You will find that the organic matter is great to recondition a bare bald mucky run with--set a bale of the hay on the ground for a few weeks, check out underneath, see how great the ground looks. If you are in wanting to start with a good draining foundation, you can dig down about 5 to 7 inches put in 5 inches of #57 washed gravel, cover with landscape fabric and cover with a 3 or 4 inches sand. then you can put in whatever organic material and know it will drain. If you run is clay like ours is, you will be using sharp sand (builders sand.) If this is for your run don't use shavings outside. They'll be wet and speed up the decay time being exposed to the weather. On the coop floor you can use everything mentioned--and the depth should be about 5 inches for soft landings--lots of folks use shavings and add leaves over the top. Whatever you decide, keep it turned daily--or have the chickens do it for you.