My run is about 5+- ft high with no top. If you clip the feathers on one wing of each bird it will help.
On some birds you may even have to clip a few secondary flight feathers.
One wing throws the bird off balance and is more effective than trimming equal amounts off both wings is my experience.
Make sure there is "NO BLOOD" in the shaft of the feather before you clip or your bird may bleed to death.