Our winters have many nights below 0 and a few days that never reach 32 degrees. I have the 5-gallon bucket with the nipples for the girls. During nice weather it has a toilet float valve inside that is connected to a garden hose that is left on at a trickle to re-fill the bucket automatically. However, since teh shed is quite a distance from the house hose bib, the hose freezes in the winter. So I disconnect the hose and put the smallest, cheapest aquarium heater in the bottom of the bucket. I start with an initial 2 gallons of water in the bucket. I carry out a one gallon container of water each morning when I open the coop. My water is outside the coop,positioned it on the south side for maximum sun exposure to heat it in the winter, and the water stays liquid all winter long, no troubles. This past winter we had about one dozen chickens and they did fine with the bucket system.
This winter we are increasing to about 25 birds. so I purchased a 50 gallon food grade plastic barrel and am going to convert that to the water reservoir to service a pvc line with nipples. I will get a larger aquarium heater if necessary, although I don't intend to fill more than 1/2 the barrel with water. But hopefully, this will make it unnecessary to carry water every morning. If I plan it rihgt, I can fill the barrel as needed on a warm sunny day with the hose and be good through the next cold spell. And I think I will need to run some heat tape over the pipes and look into whether it would be prudent to cover the pipe with some insulation to keep it from freezing. The barrel will be outside the coop, fixtures applied so that I can use irrigation supply tubing through the coop wall and mount a 10' length of pvc at the correct height, with nipples installed every 12" or so. The flexible tubing coming in from the outside will allow me to raise and lower the pvc drinking bar as necessary as the birds grow.
