This really isn't necessary.
You can build the coop on the 4x4 PT runners but I would grade out about a 4" thick layer of crusher run or road base, screed it level and run a plate compacter over it so any water drains off.
After you build the coop, attach a predator apron around the base of the...
I'd build as close to the left side of the shed as you can. Having power to the coop in northern climates makes life so much easier.
You will be able to power a heated waterer so you don't have to haul water out throughout the day in the dead of winter.
You will be able to install lights for...