Chicken Run cracks the mould

In a dark chicken shed somewhere in the north of England, the hens are planning a revolt. Led by the opinionated but plucky Ginger and egged on by the irascible rooster Rocky they are, well, hatching an escape plan.

Chicken Run, billed as the Great Escape with feathers, is the first feature film from animators Aardman. It's a love story and an action adventure rolled into one. It is also populated entirely by Plasticine creatures made by the team which first brought us a hapless Yorkshireman called Wallace and his enterprising dog Gromit.

Nick Park and Peter Lord, joint producers and directors of Chicken Run, say they have always hankered after a move into the world of film but were anxious to make sure they waited for the right moment. It nearly came in 1990 when Park won his first Oscar for the charming animation, Creature Comforts. Disney approached him to talk about transferring his Plasticine creatures to the big screen but he decided he didn't feel ready.

Then four years ago Park came up with a short sketch about a chicken trying to tunnel its way under a fence using a spoon. Aardman quickly realised its huge comedic potential and decided it would be good material for a film.

Although the talent working on the project is homegrown, the finance and background support is coming from Steven Spielberg's DreamWorks studio.

Peter Lord said: "We knew about jokes and telling stories but we didn't know how an animation would play with an audience over 80 minutes. DreamWorks' backing gave us the confidence to do it. It's a huge mental leap to imagine a Plasticine character, a few inches tall, 20ft-high on a cinema screen."

Once the idea was formed and the script was written, sketches were drawn to work out how the hens should look and storyboard artists began to set out the plot, movement by tiny movement.

During these early stages of development Park and Lord realised the practical difficulties of a cast made up of chickens and roosters. The same physical characteristics which mean chickens can't fly - a major theme of the film - made them hard to turn into animated creatures.

"The conventional cartoon character has a big head and a small body," Lord explained. "Chickens have little heads, huge bodies and spindly, fragile legs. It was a big problem for us." Since the body shape of the chicken was unsuitable for a purely Plasticine model, the animators developed a metal skeleton which was covered in latex skin. The armature had to be reinforced to bear the weight of the Plasticine head and wings.

Each chicken was created using a special blend called the Aardman mix which is stronger than normal Plasticine. They were made to look strongly individual so that the cinema-goer can easily differentiate between them. Rocky the Rooster, for which Mel Gibson provided the voice, was given a spotted neckerchief which doubled as a useful disguise for the seam of his detachable head.