The Egg Cart'n is a very large, heavy tractor style coop that has removable coroplast panels to allow for a wide range of ventilation options. It comes on very heavy duty wheels and axles, and is made with an aluminum angle frame, 10 mm coroplast, a steel roof, and a floor on the upper level made of 1/2" plastic with 3/4" perforations - heavy enough that large birds can live on it without foot problems.
It weighs 375 pounds, so it isn't going anywhere without help.
I set mine up on patio blocks to discourage digging predators. I like it. I wouldn't keep the full amount of suggested birds in it unless they had an exterior run or other range during the day - but for what I use it for, it will hold a dozen overnight and with an extra nest box, it is more than adequate for sleeping and laying purposes. It has two levels, the upper, floored level and the lower dirt level. Just toss in wood chips below.