Yes, this is my run. I live where the weather can be extremely un-nice at times, so my run is large and completely enclosed like a coop. I have two coops with only sleeping perches and laying nests which are situated at opposite ends of the run. The run is where the chickens spend most of their...
Having a blank slate is tremendous fun. Having a large shed to work with is a treasure, so I recommend you not place unnecessary restrictions on this windfall. Even four chickens can happily use the entire space of the shed.
Sectioning off the shed is a terrific idea. Storage space, however...