Howdy, we use these founts and love 'em. https://www.rentacoop.com/all-products/waterer-5gal Their site does not mention heating methods, even though that company is back east in Maryland. After two days of 28F, both founts are frozen around the edges. No more water. I'm having to put out a simple 2gal fount and replace the water every few hours. I put a small heating pad under the most important fount, which is in the chicken trailer coop where they sleep at night, but it only has 20 watts of heat. I poured in some hot water on top to kickstart the process. Do y'all think that 20w right under the fount will be sufficient? Freezing weather is forecast to continue for another couple days. Here's what our coops look like this morning.