I MADE A VERY cheap giant drinker today, all you need is a 25gallon plastic barrel with a screw lid and a plastic or tin tray about 2" deep. ..... the barrels are the feeder type that poultry feed from the bottom, the trays are maybe bakers bread trays......... drill a small hole in the centre of the screw on lid about little finger size, fill with water, screw on the lid, turn it upside down into the tray, lift the barrel a bit by putting 2 x 3/4 batterns underneath...... i first tried it with a 50 gallon barrel but full of water theres no way you can lift it onto the tray., better than the rubbish drinkers i purchased that go brittle in sunlight after a year.