There's the issue there. If they jump they are not grounded an cant get shocked so there's no point in electric more than 6 inches off the ground. You could run alternating hot an ground wires but that's hard to implement in reality.
Can electric fencing keep chickens from crossing a road. Our chickens cross the country road in front of our house and go into the neighbors yard. Our neighbors doesn't care if they are over there but he might just be being nice. Plus the road is busy with farm traffic and don't want them ran over.