You definitely want water, chickens will pick at the snow, but it's not adequate and brings their body temp down, just like a human trying to survive if stranded, you do NOT eat a lot of snow, will give you hypothermia. Metal waterer with heater underneath works fine, just run a heavy duty extension cord, you will have no worries. A lot of them come on at a certain temp, shop around on the net, there's a lot out there. We've had ours for about 8 years, and it still works fine, can unplug on clement days, which you and I don't have many come Dec., they work like a charm. Just elevate it on a large brick, or even a block of wood to keep it off the floor. Our chickens will not set foot outside in even a dusting of snow, even tho their coop is open, they sit at the door and look longingly out. We will shovel a space for them, but on bitter, bitter days, best to leave them in, they will get "cold stupid." Give them some green stuff in winter, leftover salad, peas, whatever, and plenty of corn (corn produces body heat) we just mix it 1/3 right in with their feed, it's like candy to them. Don't overdo the corn, they will get fat from it.