A chicken tractor, sometimes calle an ark, is a movable chicken coop lacking a floor. Chicken tractors may also be used to house other species of poultry, but the moniker is most often applied to chicken enclosures. It is usually of light construction so one person can drag it around the yard, and it may have a couple of wheels at one end to make this job easier. The most common shape for smaller chicken tractors is an A-frame, though any number of designs see prolific use.