I want to share my solution for frost free, no electricity drinking water for my chickens. I searched high and low for ever to try to find a solution online, and the following is an amalgam of different ideas that has so far worked perfectly for me, and has cost exactly zero dollars. This idea could be scaled up somewhat I think, to suit a bigger flock, but there would be limitations with regard to materials, weight etc. i am in a relatively cold area, (Denmark-Scandinavia) with daytime temps of around 20 degrees farenheit ( minus 6 celcius) dropping to around 10degress f, but rarely lower in my area. i don't know how effective this would be at lower temps, but it has so far proved to be very effective, with very little input. i wanted something portable, ( to follow my chicken tractor around with my five chickens) electricity free, and automatic, in the sense that i wanted the water supply to the chickens to be constant, clean and unfrozen. essentially it is just an insulated automatic gravity fed waterer, made from an old polystyrene cooler i had laying around, with a couple of plastic jugs, and some minor modification, in all, about 30 minutes work. a couple of things to consider:
(1) the waterer needs to be on a level surface, i have mine sitting on top of a piece of concrete, off the ground.
(2) the drinking access hole needs to be small enough to restrict temperature transfer, but big enough that the chickens feel safe to insert their heads. mine needed to be 3 inches in diameter before my chickens would put their heads in it to drink. ( i experimented) i have isa browns and Icelandic chickens. This could vary for different breeds, i don't know. # IMPORTANT! chickens eat Styrofoam, so the drinking access hole needs to be sealed, i used a piece of plastic pipe inserted into the hole i cut with a holesaw.
(3) the outlet hole in the water supply jug needed to be 3/8 of an inch to allow water/ air transfer to be effective.
(4) the height of the drinking access hole needs to be considered, depending on the animal, but also considering the outlet hole in the jug for the water to pour out. after experimenting, i put the outlet hole on the TOP of the jug, near the handle, for convenience in refilling and carrying. i insert the jug upside down in the cooler when i want to start the waterer working. this way i can carry the jug, before and after filling, using the handle for convenience.
(5) to calculate exactly where the outlet hole in the water jug needs to be, you need to measure the level of the LOWEST point of the drinking access hole, and make sure that your outlet hole in your water jug is BELOW that height! otherwise your automatic waterer will pour out the drinking access hole until it is empty.
(6) one jug inside the cooler is just for thermal mass, it is filled and sealed with ordinary water, i have used hot water inside this jug when temps are particularly frosty out, with very good results, otherwise, its not necessary, you can bring the cooler inside a heated dwelling overnight, to keep temperature up.
(7) make sure there is enough free space and water surface for the chicken to insert its head and drink comfortably ( see my awesome diagram!)
placement of unit. i have mine outside the portable coop, on a brick, surrounded by bales of hay, with old windows on top, allowing the sun to provide some additional heating to the unit. my chickens also enjoy the space under the windows during the day as its out of the wind and it is warmer under the glass. all of these things combined have made this waterer as easy as i would have hoped! i tend to my chickens every day, but i have had occasion when i haven't been able to, and the waterer has functioned perfectly, without frost, even when outside water is frozen. i usually top up the water every day, but depending on many factors, the water supply can last many days without any input from me. i have been very pleasantly surprised on many occasions when i thought i would be in trouble with frozen water. a high quality, heavily insulated cooler would be a plus, as mine is very thin and cheap, as would having it black / painted black to absorb solar heat.