(... The poll did ask about 'Other' types of waterers, so I guess this fits in here...)
Sometimes, giving a second life to items in your possession is the key to success. In someone's case on another site, they went the simple yet creative route and gave their rice cooker the new task of heating their chickens' water. Plug in the item, pour water inside, and set the cooker at 'warm'. That was all.
From the comments following the original one, re-purposing a rice cooker into a heated poultry waterer apparently works, as both the original person and the one who told them the idea are now using rice cookers to keep their chickens drinking during the winter months. There were no pictures attached or brands named, so I will assume the lids are kept open so the chickens can drink inside the rice cooker. Its level of maintenance, energy costs, pros and cons (and potential fire hazards) are not mentioned.