Same thing happened here. I ended up with 11 mallard ducklings. I already had 5 ducks that I brooded 2 years ago for my pond ornaments and one pair of them brought in 11 more at one time. Now the pond will be way too small for this many. And what concerns me more is what if they start breeding in the future too? That's some serious multiplication. They are cute though in the meantime, but they will be troublesome as they all grow up and compete for the same resources. Maybe some will eventually fly away. None have yet and I have never clipped them, nor do I intend to.