We use a heated dog dish that only comes on if below 40 degrees - and its been down to -5 here already. We use heavy, outdoor rated extension cord with a "cover" that covers the point where the extension cord and dog bowl cord join. It has little gaskets that prevent water from getting into...
We used one of the coop designs on BackYard Chickens and modified it a bit. We were also building a shed - so we combined the two with a shared back wall. The coop part is 7 1/2 feet by 9 feet with a raised floor and 3 nest boxes. We recently added a "dog kennel" run that is 15 ft by 5 ft...