Well with lots of drakes you'll have plenty of ducklings. and with 10 acres they will have plenty of room to stay out of each others way. Plus even though hardy and can fly you'll most likely lose some to preds, especially if the females nest where they haven't any protection. As for their poop filly up holes making a seal that I haven't heard of that.Well.. I know its going to sound crazy but these will be working ducks. We have a pond about an hour and half away from where we live. My husband and his family have built a bunkhouse/cabin and we go up there at least every other weekend. The pond doesn't hold water well but has a well that pumps water to it 24/7. Because of this the water weeds and algae have taken over and the fish are getting over populated due to the fact that the water weeds are making it hard to fish. I had read somewhere that duck feces could help create a seal for the pond to hold water better and that they would eat the fish, algae, and hundreds of bugs. Cattle are ran behind our property, but the ducks will have about 10 acres to roam, forage, and live. I dont want to clip their wings since I want them to be able to fly away if a fox or coyote gets close. They will have plenty of buildings to fly up on to get up high, as well as trees, and we are also building them a fly in roost that would protect them from the weather/predators. I do worry about leaving them down there when we are not there but this is why we bought them and from everything that I have read and researched, they are extremely hardy. I just didnt think in my wildest dreams that I would have ended up with so many drakes!