I run my electric fence off a car battery (I have a spare battery on trickle charge in the shed). The fence is primarily to keep the pigs in,but the chickens won't go anywhere near the white nylon rope electric fencing,it's set at 4inches and 12inches above ground height. The stock fencing is for sheep and the chickens can get through it in other areas. A 500 metres long strip for chickens does seem somewhat excessive,(although I don't know the size of your flock),so why not go for the electrified chicken netting and strip graze them? Or how about a movable ark with a simple enclosed run that can be moved daily?
BTW the world record for chicken flight is a distance of 13 feet,so clip one wing!