The run I have for my 5 girls is approximately 600 sq ft (20'x30'). It is a fenced off area on the side of my house, bounded by my neighbors fence, the fence around my backyard, my house and the 4' snow fence I added as a temporary 4th wall of the run area. There is a 30+ year old cherry tree about 10' from my house and both of my border fences.
I have raked the area a couple times since May when the birds were moved to the run. All I have collected is some cherry leaves that have fallen as well as, all of the grass tufts the birds have scratched loose, as well as a bunch of chicken droppings. At this point, aside from a couple of areas the girls have scratched out dirt bath wells, one neat the house where there was only dirt to start, there is grass in the areas not under the tree, and under the tree is both grass as well as 2 low height ground cover.
In the run I have a coop where the girls sleep and for inclement weather. The roost area is 9 sq ft, and there are 2 nesting areas, each ~ 3 sq ft. The floor of the roost area, which I scoop daily is covered with mostly sand blended with diatomaceous earth and a coop-refreshing granule. In the one nesting area there is one nesting pad as well as one area with water, and another with food. The 2nd nesting area has one area with a nesting pad, and the other 2 areas are a blend of primarily a hemp shaving atop diatomaceous earth.
Moving forward I may try planting a cover crop of some type in the area not shaded by the tree. I was thinking of trying clover, marigolds, calendula, strawberries, oregano, lavender, mint and/ or basil. Knowing that I will have to block off the area where I plant all of these, except the clover until the plants are fully established. Additionally, I may try to connect with a local tree service to get some wood shavings for areas where the ground got waterlogged after it rains.