Ok, so I've been working on clearing the bramble in the yard, and discover an somewhat small dog run. The dimensions are approximately 10ft x 10ft x 4ft and on a concrete slab. The concrete slab extends a foot or two beyond the edge of the run, but is also the flooring through out the inside of the run. Now, would it be ok to have the girls running around on the cement (maybe have a layer of wood chips or even soil for them) or should i consider breaking the concrete inside the run, or finding a different location,so they are on direct soil?