After losing my four hens to a bear attack on my coop, I'm looking into installing an electric fence. I can run electricity to the coop so I won't need a battery operated model. The local feed/grain/hardware store has a few different energizers, most of them the brand Fi-Shock, and I'm not sure if any of them are the right size to repel a bear. Most were in the $25-$35 range, with the highest price being $79. The packaging seems to rate them on the size of the area they protect. Since the bear was able to lift off the top of the coop, tearing out the latch, I plan on running the electric wire around the top, so he'd be sure to touch it if he comes back. I'm pretty sure I can install this so he touches a wire with his paw (or at least leans on the wire) while he's also touching the ground. I should be able to screw the insulators directly into the wood of the coop, and the store has 12 gauge wire. It will only take about 12 feet of wire to go around the coop once, but I'll probably make a couple of loops to make sure he gets jolted. The thing I can't figure out is what size energizer to use. Can anyone advise me?