Consideration and idea's for ground cover for your feathered friends.
You might consider planting bulb plants that are not toxic to the hens as they grow back. Also consider planting Millet and other bird seed which grows up high but creates a little bit of a forest etc so some Hens can either get away from the others or hide or have some alone time. Birdseed grows very easily. Some people will have a long long run and will simply block off part of it for a month or so and regrow seed in it etc, depends on room time and circumstances really. There are also some natural weed type plants or plants that are considered weeds I cannot think of the names right now, one weed for example that they use to use for marsh mellow flavoring in the old days before artificial flavors came out, my hens like eating it but are never able to eat them down completely cause they just keep coming up and up. Look into some of the natural plant weeds that are actually edible for people as they provide great ground cover and just keep coming up no matter how hard the Hens try as the Hens only eat at them off and on whereas grass they chomp on constantly.
If you are afraid the bird seed plants will attract wild birds to much just go for the edible weed plants which is a good pick along with some non toxic bulb plants that keep coming up over and over again.