you do not have to heat the ducks' water.
when I had ducks and geese, they would swim
in a broken hole in the ice on the pond..
remember, the water never gets below freezing despite how cold it is around it..
I did not read all of the posts, so this might be a duplicate answer.
I went to our local building supply center
(Menard's) and bought a mud mixing boat.
that is the contractors' term for it.
what it is , is a rectangular rubber tub.
about 2 feet x 3 feet by about 8 inches deep.
It holds...