Ducks are supposed to be fine without food & water for 8 hours.
i leave water because I prefer to leave food with mine so they can eat to boost their temp if needed. I leave 1/4 to 1/2 full bucket (Don't fill more than 1/2 full at the very most or they will throw it on their backs to bathe & soak the entire coop!) in a hollowed out area of hay so they can't knock it over. I put in very warm water and swap it out every three to five hours before I go to bed so they have the warmest (but not too hot to drink) water possible so it will not freeze & so they don't have to fight to keep their internal temps up.
I let them have ice cold water and cool thawed or frozen peas in summer to cool them down.
in the winter I thaw and run frozen veggies under hot water to warm them up before giving them to them.
I know many people do not put water in their coops but I see them drink all the time & can't imagine them without water.
Then again, I heat their coop. I fight wetness of straw from the heater & them pooping A LOT! I periodically remove newer layers of straw & put down Sweet PDZ or barn safe lime and then fresh straw on top. I put down a little layer of fresh straw often when they are stuck in their coop day & night to keep it drier for their feet & so they can stay warm.
When my boyfriend gave them cool water one evening when I was gone, he said they all quacked loudly until he brought them warm water instead. He said they quieted down & happily started to drink. I thought he might have been joking a bit but he said they would NOT quiet down until he brought them warm water.