Use a horizontal cross brace. Attach a 4' run of chicken wire taught to your supports 6' on center, with the extra length aproned out to discourage diggers. Attach a second pieace of hardware cloth on the verticals, so it overlaps the bottom piece by 2" - 3". Secure it to the coop along the top and sides.
Now attach a horizontal support over the overlapped chicken wire, and secure the wire to it from the inside of the coop - screws and washers. Now you have no entry points, a rigid top/bottom edge, and a piece of wood at convenient height for hanging things off of later.
Don't forget to use something weather resistant, cause its exposed.