Little Giant Plastic Poultry Drinker 3 gal is made of plastic so placing on a metal hot pad will damage it. The Little Giant Double Wall Metal Poultry Fount 3 Gal. would be a better option.
Per the manufacturer, if the water is not coming out it might be the cause of static build up. They recommend that for the first time use of your LIttle Giant Plastic Pountry Drink 3 Gal., wash the whole white jug with warm soapy water and to do this frequently as well to avoid any vacuum effect.