A chicken walker is a fictional type of bipedal robot or mecha, distinguished by its rear-facing knee joint. This type of articulation resembles a bird's legs, hence the name. However, birds actually have forward-facing knees; they are digitigrade, and what most call the "knee" is actually the ankle.
They are usually less able to handle extremely rugged terrain than "man walkers". They are often shown to be faster than other robots, capable of roadrunner-like movements. The best example of this contrast in film is the fast pursuits of the ED-209 versus the steady walking pace of RoboCop in the RoboCop franchise. Also, in the Star Wars franchise, the chicken-walking AT-ST was used as a light scout vehicle rather than the AT-AT, which were lumbering quadrupeds.