The Cozy Hen™ uses a patent pending design to resist freezing in winter weather. High tech insulation is used to slow cooling, and a heat pipe is used to conduct heat from the warm water in the inner bucket to the drinking end of the watering nipple. Without the heat pipe, the drinking tip of the watering nipple would quickly freeze if the waterer were placed outdoors in freezing weather.
When the waterer without a heater was filled with water at 105⁰F and then tested outdoors at 0⁰F, it took more than 10 hours for the nipple to freeze. When the waterer with only a 15 watt heater was tested outdoors at 0⁰F, the water in the inner bucket was maintained at 78⁰F, and the tip of the nipple was maintained at around 70⁰F. (See the "Typical Performance of the Cozy Hen™ Waterer" page on this site for more information.)
The following bottom view of the Cozy Hen™ Waterer in sub-zero F weather shows the 'hot nipple' assembly. Although a thin coating of ice is visible on the outer shield of the 'hot nipple' assembly, the nipple valve is not frozen and delivers liquid water.