My ducks are currently in a 7'x12' enclosure made from a modified cattle trailer (sans wheels) covered in chicken wire. They have a large dog house and a little swimming pool (round, 6' diameter, 1'3" deep) to play in. There are 5 of them-- 2 girls (a khaki campbell and what looks like a pekin-khaki mix) and 3 boys (a khaki campbell, a pekin, and a rouen). They're about 2 months old now.
We have a fairly large pond, maybe 3/4 acre, that currently has only some fish (catfish and whatever other breeds my father-in-law put in it) and normal pond flora. There's a small island on one side of it, probably 10 yards or so across, about 5 yards from the bank on one side. It looks like a great pond for ducks, and we even had a handful of mallards stop in for a few days about a month ago.
I'd love to move the ducks to the big pond. However, I worry about predators. We have some small dogs (all under 20 pounds) that wouldn't bother them, but I worry about our neighbor's dogs. He has 3 or 4 dogs that have come over on at least 6 occasions and mauled our dogs; while none of them have died yet, the injuries sustained have been pretty serious, ranging from punctured lungs to near-evisceration (and vet bills totaling several thousand dollars). Much of our border is fenced, but even if I fenced the thousand feet from the road to the woods, the dogs could just go around it on either end... Anyway, my point is that the neighbor's dogs could get our ducks.
Adequately fencing the pond would be expensive (chicken wire costs alone would be over $400), but also complicated since it actually belongs to my father-in-law.
What other methods exist to secure a pond for ducks? Would it be sufficient to put a duck shelter on the little island and let the water serve as a natural barrier? Are the ducks actually in danger, or am I underestimating them?