Ditto. Six to seven foot (or even higher) fencing plus a wire roof makes for a safer run that'll keep everyone inside and aerial predators out plus make it easier for you to tend to your birds and interact with them. I don't like clipping wings as a solution. Some determined birds will learn to 'walk up' a wire fence, flapping furiously all the while they climb with their feet, no matter what the fence's height, so the clipping doesn't even necessarily work to contain jokers like this. Also, once you remove your chickens' ability to fly straight up, you may have to rearrange your perching options or provide a chicken ladder or they'll be grounded at night. I personally consider an ability to fly a bonus for my chickens since I let them out to free-range when I'm home. The buff orpingtons and commercial hens I have now I'm always a touch worried about when they're out since they can't fly worth crap...the olive-eggers could at least fly up on a roof should anything like a crazed raccoon or mink get into the yard with them. (Both of which have happened during the daytime despite my being present, by the way.) Anyway, stuff to think about...
