Drakes breed ducks. It's normal. If they did not, there would be no more ducks. It is not necessary to keep drakes in a flock unless fertile eggs are desired. As a matter of fact in those instances where drake numbers are excessive the hens would be happier with fewer or no drakes. A sensible decision for those not wanting to observe mating behavior might include separation of sexes and culling of drakes. For me it is difficult to "hate" that which is normal behavior.
