In keeping with the film's story, the game takes place on a 1950s Yorkshire chicken farm and follows a group of lovable chickens as they try to break out of confinement.
Players must help Ginger and her flock make a break for freedom while avoiding the evil Mrs. Tweedy and her oafish husband, who wants to turn them into chicken pies.
When an American rooster named Rocky lands in the farm, Ginger sees her chance: these chickens won't cross the road - they'll fly the coop. Together, they prove that chickens are anything but chicken, as they engage in a daring and spectacular escape.
Source: Wikipedia, "Chicken Run (video game)", available under the CC-BY-SA License.