You can clip the wings. If you search the topic on google or yahoo, there are several good videos on clipping chicken wings. Its not that hard to to do. I clipped on of my RIR's. Also I seem to remember a thread or on BYC on clipping. Good luck.
Very interesting that you ask this. When I first got chickens, I read that the type of Hens I have are not good fliers. 4 feet seemed to be the right height. Well now I just spent the afternoon raising the fencing up another 2 feet because i have a few escape artists. Moral of the story is, 6...