Waterfowl must have water deep enough to submerge their heads, in order to rinse eyes and nostrils. If waterfowl are kept on the same pasture with growing chickens, however, the chicks can fall into any sort of open waterer and drown. Here is a solution for drown-proofing a waterer deep enough for ducks and geese to submerge their heads.

I cut off the bottom one-third or so of a 5-gallon food grade plastic bucket. (I drilled holes in the bottom so it wouldn't float when placed in the tub.) I set it bottom side up in a 6-gallon rubber watering tub, to which I attached a float valve on a supply hose. Watering is automated; the waterfowl are able to dunk their heads; and chicks who fall in are able to scramble up onto the rim or the upturned bucket bottom, rather than floundering around helplessly in an open waterer.