I water my 28 hens with a couple of 3-gal. plastic buckets with nipple waterers in the bottom, hanging from the ceiling of the coop. This will be my first winter so I trying to decide the best way to keep the water flowing in my (unheated, NE Wisconsin) coop. I am thinking some kind of heater suspended in each bucket will work. What kind of heater has worked best for you in similar situations? I stopped by Wal-Mart to look at acquarium heaters and there was one for about $18 but it will keep the water at 78 degrees farenheit which seems like overkill and might use more electricity than necessary. I also found a couple of 44-watt and 50-watt submersible birdbath heaters on Amazon.com which look like they might work. I would prefer a heater which is thermostatically controlled in order to save power consumption. Any other suggestions? Thanks in advance for your help.