They have come of age where hormones are running rampant. either you'll need to rehome them or get them some ducks 3-4 each might make them happy. And yes keep them away from your hens, they will try to mate them and it can be a death sentence for them. As far as why they won't go in the pond, do you have snapping turtles? they will bite feet right off of ducks. and eat ducklings.