Here is the link for an automatic waterer that attaches to your garden hose. I am looking at the same issue for my 22 ducks as well. I am trying to make ducksitting as easy as possible for friends and family for those few times my wife and I head out of town.
http://www.horse.com/item/automatic...code=GPHORSE&gclid=CL_X4oaHvL8CFW4Q7Aod7VwApg
Fortunately for me, my duck pen is about 75' from the well and I already have enough hose for it. Unfortunately that is 75' of hose in direct Florida sunlight, so for most of the year the system will provide them with a bowl of very hot water. The other option would be to set the faucet to a slow drip, then let the water slowly fill into a reservoir (in the shade) then a small pool. That way by the time the water gets to the ducks, it will have been out of direct sunlight and at least tepid enough for them to drink.
http://www.horse.com/item/automatic...code=GPHORSE&gclid=CL_X4oaHvL8CFW4Q7Aod7VwApg
Fortunately for me, my duck pen is about 75' from the well and I already have enough hose for it. Unfortunately that is 75' of hose in direct Florida sunlight, so for most of the year the system will provide them with a bowl of very hot water. The other option would be to set the faucet to a slow drip, then let the water slowly fill into a reservoir (in the shade) then a small pool. That way by the time the water gets to the ducks, it will have been out of direct sunlight and at least tepid enough for them to drink.