This is less of a 'problem' than a 'I thought it was funny and wanted to share" story.
Our 6 ducks are enclosed in a massive fenced pasture with the 45 chickens, with free access to all the coops, the barn, and some woodland. Some of the chickens go into the pig pens if they're smart enough to avoid the electric wire.
For the most part, there's no problems. Of course, some of the older hens are a bit territorial and peck the duck hens (never the male) until they leave around the food. One hen, unfortunately, seemed to have decided to get between the ducks and their water. I came outside just in time to watch a cayuga female (always gentle, docile, and passive), ripping tail feathers out of the hen and chasing her away, bill opened and wings flapping, the same way our drakes used to chase each other.
The poor hen learned her lesson: never get between a duck and her water!
The duck went back to drinking with the other ducks, side by side with the other chickens, but she will not tolerate the presence of that one hen any longer!
I don't think the drake even knew what to do. He just watched her do it, then went to his usual mating rituals.
Anyone have any stories of ducks "losing their patience" with their bullying counterparts?