That fence will not protect them enough to where you can have 'just a dog house', without lockable doors. Any racoon can scale that fence and eat a chicken dinner without a second thought. The electrical line will help with foxes, coyotes and maybe bobcats, but racoons will learn to climb a tree and jump over the fence, then climb the fence and jump over the electric wire on their way back. You will want to build (or tweak) a 3'x4' box that has a slanted roof; is raised off the ground; is water proof; has a 2"x3" roost; ventilation at the highest point possible; a large, lockable cleaning door, maybe one whole wall as the door; a pop door you can close and lock; and an egg box you can access from outside. This will make it much more enjoyable to own chickens, because it will be easier to clean the coop, gather the eggs, and keep them safe. This may sound very fancy, but a lot of these things you can find in a dog house already, or take a moment to install on a doghouse.
Roof? Dog houses usually come with these, along with four walls and some form of framing.
Raise the coop? Before you begin to change the doghouse, scavenge or build a table to the size of the doghouse, about 2-3 feet off the ground. Set dog house on top of table, screw in place. You can hang food below the coop, out of the rain. Why raise the coop? So you don't have to crouch when you clean or gather eggs.
Ventilation? Drill several large holes on both ends of the house, at the peak of the roof line, under the overhang. Drill some holes in the back of the nesting boxes. Carefully cut a hole in the side of the dog house door, cover with 1/2 inch hardware cloth. Keep cut out piece to fit over 'window' in the winter.
Doors? Use a jigsaw to cut a hole where you want the nest boxes to be. Use the dog- door as a pop door, cut a piece of wood to fit, install hinges/lock. Pry off one wall for access/cleaning door. Remove nails/screws. Install hinges/lock.
Nesting box? Create a 2"x2" frame box big enough to fit over the nest box hole. From inside of dog house, screw through plywood wall into all nesting box 2"x2"s that touch dog house wall. screw on some plywood walls cut to fit the nesting box, leaving roof or side as a door, and install hinges/lock. Maybe add some support for the nesting box by making two 2"x4" 'legs' for corners not touching coop.
Roost? From inside of coop, install a 2"x4" beam that goes from the ceiling to the floor on either end of where you want the roost. From outside of coop, drill through plywood wall, through 2"x4", and into 2"x3" roost itself.
Ramp? Use a scrap piece of lumber about eight inches wide and four feet long. From under side of ramp, nail through plywood into 1"x2" rungs. Screw top of ramp into coop using hinges, just below pop door. weigh down the end of the ramp that touches the ground with some rocks. Make sur you have enough rungs and you can still close the pop door.
Consider painting everything with an exterior grade paint, so you can just wipe it down when you spring clean.
In this coop you can keep three large hens, or five bantam hens. I hope this helps.
