I was wondering this too, hopefully we get an answer (since this thread is kind of old). I'm thinking maybe its a dirt floor coop?
I have thin sheet metal down in my coop. I think 12 or 16 gauge. It works great for scraping, and all goes right out the poop slot. Easy so far! But I noticed frost build up in the corners and along walls where the walls meet. Also, frost near the bottom of my coop where the walls butt into the floor. Seems like all this moisture will eventually take a toll on the new coop building.
Note; I am in a very cold climate. Alaska! My cool has ventilation issues.