Dunno.
Chicken Foyer sounds like something that might show up on a plate, or introduced as something new on one of those competition TV battles of the chefs.
If you have a raised floor n your coop, and your chickens are contained in there, they'll certainly scratch up any litter to keep the toesies warm.
My own coop is of common wood-frame construction. a simple two-by-twice as a bottom plate above the floor.
Whether for warmth in the winter or for absorbency any time of year, 4"-8", as your chickens will arrange it to suit themselves, could be hard to contain.
Not hard at all. I nailed up some 1x4s inside the studding of my various doors. What spills over to the point that it might interfere with the operation of the doors is easily swiped away by hand.