Good idea with the lattuce work depending on where you are (and I really didn't look I guess). In my area, it would work GREAT! You actually gave me a good idea! It doesn't get very cold here in NE TX. I don't think I will do all 4 walls that way, but the lattuce is a heck of a cheap fix for something I was thinking about for my coop.
That being said, I'm a complete newbie and have only had chickens for 7 weeks. I don't have a clue as to what I say so don't listen to a bit of it. I would worry about predators being your on the ground. I have a friend that has a coop that he put a 2x4 all around the ground to keep out creepy crawly stuff and then put the coop a couple of feet off the ground to keep out other stuff. He still has trouble with foxes. Point being is that I am a welder by weekend, yet I am having the toughest time trying to come up with a chicken coup. Go figure!