A duck being attacked!!!
- Overrun with Runners
Well, remember that her life depends on you. So separate her. Temporary fence can make a good divider so she can see the flock but not be harassed. Or you could separate her with a female buddy.
Or, better, separate the drake from the girls for a while.
Changing up the dynamics often improves things. But it is a try it and see kind of strategy - there is no way to predict exactly what will work best.
But always remember that the safety and health of each member of the flock depends on you.