Your only concern is probably keeping fresh water in front of your girls. There is an electric heater base that is available commercially, but if you don't have electricity in your coop, you can simply have two water bowls and swap them out twice a day. Put out a fresh bowl of warm water in the morning and take the frozen bowl in the house to thaw. In the late afternoon, dump the melted ice out of that bowl and take it outside with fresh, warm water to replace the one that is probably frozen by now. You can use dog bowls that have wide bases so that they won't tip over if the hens decide to sit on the edge.
You don't need to spend money on products such as those on this page, which merely use "passive solar" to keep the bowls from freezing -- that means that if the bowl sits in the sun, it won't freeze. There is no "technology" involved in these bowls, regardless of what the manufacturer says. And their battery operated heaters are an environmentalist's nightmare. It makes no sense whatsoever to use eight -- yes, eight -- D batteries to keep a bowl of water from freezing overnight. The batteries are dead in less than eight hours, eating up one battery per hour for no reason. If you give your hens fresh warm water in the late afternoon, they'll be fine until morning. And if they have access to snow, they'll eat that, which contributes to their water intake. Chickens actually drink very little in the winter anyway.
As for insulating or heating your coop, don't do it. Chickens survived just fine for centuries living in makeshift coops made from barrels or whatever scrap wood was laying around the farm. It wasn't until the 1870s that commercial chicken keeping took root, and people began putting chickens in insulated, heated houses, thinking it would make them lay eggs through the winter. By the time they realized their mistake, confinement chicken production was considered the standard. People also saw a huge increase in poultry diseases during this time, and by the early 20th century, some people were advocating a return to letting chickens go outside. Research showed that the above chicken house, which had no wall on the south side, made for healthier chickens, but most poultry producers would not be swayed. The debate raged on for about 30 years, and we all know who won. Today confinement chicken operations are the norm.
|Our chicken house -- notice the open windows for fresh air?|
Don't open windows on opposite sides, however,
because you don't want wind blowing through the coop.