40 chickens, 3 turkeys, 5 ducks, 5 geese and 1 Red Golden Pheasant.....
1-5gln plastic pail, apiece of 1/2" plywood cut to18x18" and another cut to into diamond of top of pail, 2-2"#8 screws, 1 pce of 1x4 about 4" long, a pigtail socket, a piece of electrical conduit(cord)with a male end(prongs), a 40-60watt bulb, a 2" or 3"hole saw bit for a drill. Draw a line all around the pail 4"" from the bottom then "hole saw" holes with bottom of holes on the line. Attach circular plywood to square plywood by screwing through both into 1x4 to be used as "handle", drill a small hole in the plywood to put conduit through, wire up the pigtail and put in bulb, suspend bulb about 5" above the top of the holes by using goop kind of glue on cord/lid junction.  I put the contraption in a large aluminum cookie tray and put fresh water 2x a day. It doesn't freeze unless it gets really cold(-20*C). Problem....it adds moisture to coop interior. 
I use the same method for waterers in the pigeon coops. 
I still have water dishes outside too. Usually stainless steel pots wider at the top than the bottom. That way if it freezes it's easier to get out.
I like to keep water birds in a different coop because they like to "bath" in their water or at least "slobber" making a mess inside.
Pigeons are also housed seperatly.