Concrete foundation and apron questions

[Shezadandy]

I don't see any issue with the skirt and hay bales, I doubt any rodent would dig 2ft+ to get into the coop. Perhaps if there was existing holes from a tunneling animal, like a mole - that's what happened in my old coop, we have lots of moles everywhere getting the worms

Norway rats - will do anything. Massive tunnel systems. Climb the walls, chew through roof vents, right through siding, climb right on in ... unless there's hardware cloth blocking their progress- they will do anything to get in.