We use mulched leaves and grass clippings in our not covered 7' x 30' run that is for "free range" time for our four chickens. I never need to scoop out the poop, just let everything decompose in place. The finer materials let the moisture seep through to the dirt below, so it is much more absorbent. It has been well received by the chickens to have a soft bedding to walk on and scratch around, and help us to be more environmentally sustainable.
Last year, we put the un-mulched leaves and pine needles directly in the same run. It didn't compost, didn't absorb moisture, did not work out well, had to scoop out everything for leaves collection. So mulching the leaves and pine needles was the key to manage moisture and speed up compost.
Inside our coop and the attached covered run, we use pine shaving, poop board and deep litter method, it has been very low maintenance.
Rather to mulch the leaves or not might have to do with the size of leaves and ratio to other materials. We have alot of ash trees and red maple, both leaves are small compared to the sycamore or white oak leaves for example. I also have alot of grass clippings in the run along with some straw & pine needles. The pile of leaves was dumped in late afternoon and had pretty much disappeared by morning.