I have deep litter in coop and dirt in their run, used to have grass. I add to the dirt in 1/3 of the run with wood ash etc...in the middle 1/3 ha've hard ground where their food and water is, the rest of the run is under the coop there is dirt and some grass. If the run is lightly watered on occation, grass will grow in the area of the run not covered. We have 12" of hardware cloth buried around the whole coop and run, but moles still dig their way in. I should add, they only go into their coop to lay eggs, they sleep in the run then they are out running around all day. They're so cute