I would suggest at least a 25 mile charger for your perimeter wires. It sounds like overkill but there's no way a dog is going to go back for more after getting hit by that. I use a 25 mile charger on my net fence and I have the coyotes running scared.
A big charger is deffinitely effective, I...
I don't think the chickens will be able to reach the wire because it will be on the OUTSIDE of the run fencing. It would only be affecting critters trying to get in/under the fencing.
There are wire fences and net fences. You could just run a couple wires or get a net fence. Both will need a charger and a ground. I have a net fence, its portable and keeps the hens in and the predators out. Since you already have a stationary fence, you might just be better off stringing a...
Why don't you put a live trap out with a can of wet cat food. I'm 100% sure that you'd get yourself a masked bandit. That is MOST DEFINITELY a coon in your game cam photo. I'd bet money on it.