I simply can not have my chickens going over the fence ever again. As well I don't want to be anxious about chickens going over the fence, so I "fixed" the problem. I eliminated, or at least highly reduced the possibility of chickens going over the fence.
Here are the numerous steps of my solution:
Step 1: Lock the girls up about an hour before dusk. It appears that they search out the perfect roost rather than quietly roaming into their coop. So I eliminated the options - coop it is.
Step 2: Clip their wings. Clipping their wings was relatively easy. Catching them was the hardest part - after that they relaxed and submitted easily to the clipping. I don't have any pictures, but check out this link to give you an idea what they look like before and after.
Step 3: Raise the bar, or at least the fence. I added additional fencing to their run, increasing the height by about 2 feet. The addition is flexible so if the girls somehow make it up there I hope they become extremely disoriented by the shifting surface and flap back over to their side of the fence.
It has been a little over a week and no more chickens over the fence, or even trying. It seems a few natural steps have taken place as well. The first one is time. Let the girls get used to their home and they don't want to leave. Second, they have found the roosting perch in their coop. So no more searching for a place to roost for the girls, it appears they have found it. :)