Hello, I am exploring ideas for a water heater in my coop. Their standard 1 gallon red and whiter jug freezes everynight. For whatever I actually end up choosing, I will need to use an extension cord from the house because I don't have electrical out in the coop. Are there any general precautions/guidelines I need to keep in mind dwith extension cord use? I don't want to create any hazards. Thanks!!