I have a mixed waterfowl flock of 16 standard ducks, 2 geese, 8 calls, and a mixed flock of 17 chickens ranging from OEGBs to Brahma. I go through 300 pounds of feed a month in winter. Significantly less in spring and summer. They all eat the same feed at 18-20% protein. The ducks are absolutely pigs. They hammer food. I keep no food or water in their coop, though. They eat during the day. I will say that the ducks far outperform the chickens in regards to laying, so at least they earn their keep.