I have a 2-year-old Pekin duck that is constantly pecking at my hens. I have already lost 3 hens to his pecking; I also feel that he killed my rooster. We separated him from the flock for a bit, let him out today and he was right back at it.
What do I do? Is there anything I can do? Or do I need to just get rid of him?
Ducks -- especially drakes -- are exceptionally horny little creatures. If he lacks any ducks of his own, then he is most likely attempting to get his fix by mating with your chickens.
Unfortunately, ducks have a more rough way of mating than do chickens. Chickens just hop on, scrabble a little for a foothold, do the thing, and hop off.
Ducks, on the other hand, seem to have more of a habit of grabbing and pushing/pulling on the head. They also usually mate in water, wherein they are more buoyant and can do such things without quick as much stress on the bottom of the pile (ducks can and will form little towers of two or more birds to mate) due to the floaty, bobbing action that mating causes in the water. On land, however, there is no such floatiness, and the bird is just being pressed into the hard ground whilst being poked and pulled at during the act.
Ducks also mate several times per day, due to the aforementioned generally horny state of the birds -- especially the drakes.
Chickens are not made to withstand such harsh, rough treatment, and certainly not multiple times per day.
I, personally, would simply get rid of him. Either try to sell him off to someone, or just off him yourself. If the latter, you can either prepare him for eating or just dump his body well away from your and anyone else's coop.
If you really want to keep him, though, I would get him female ducks so that he can do the deed with his own kind.
And if that doesn't work or you thing that he may just be a jerk, please just refer to the above statements about getting rid of him if you deem that the way to go.
For good measure, I'll tag a friend of mine who has had more experience than I with ducks.
@Overo Mare, could you please take a gander at this if you have a moment?
