Go into the coop section and look at the models of tractors that are posted there.
There are A frames and long frames as well as double deckers.
I love mine and find them most useful for pasturing the chickens. I can move the coops to a new pasture and leave the chickens in the tractor for a few days before turning them out to free range. They always go back up in the tractor to coop up at night so I can close them up and keep them safe from predators. When they clear out an area around their tractor I move it another 20-30 feet. Mine have wheels but some people just use runners or skies on the bottom of theirs.
Works very well when you have special flocks for breeding or lots of acreage that can be used. I have Araucanas in one and Barnevelders in another. The Welsummers are having one built right now and the Buff Orpingtons are in a small one near the barn.
Little Chicken Racing Team,
That is eggsactly what kept coming to mind when I would read about chicken tractors!
What ever happened to the old fashion "chicken pen"? Its like calling a housewife a domestic engineer!