My horizontals did freeze up on the outside cup overnight when temps were -10 or lower over a week or two period last winter. All I did was hold the frozen nub and rub it with my fingers for a moment in the morning when I went out to feed them and it melted right off and started running again. I'm very pleased with them.
My new black farm cull seems to know how to drink from vertical nipples. My bucket is too low but she has been pecking at the nipples like she knows what she is doing. Exactly how do they get the water into their mouth/beak. Im thinking they need to have the nipple above so the water can drip into fhe beak? Also how much do they get at a time, each peck?