Jpat has a good thought. Corn doesn’t provide enough nutrition, especially for a flock of ducks your size. Tractor Supply sells up to 50 lb bags of poultry feed for under $16.
The ducks needed a little holiday cheer so... I made them an edible lettuce Christmas tree with a squash star and tomato ornaments. From my family to yours, Merry Quackmas! ❤️