I've got a Muscovy female with a similar problem. I've had to shut her in on her own for a bit to let the scab heal properly. She gets away easily during the day but at night.....So far it's just the one hen that had a problem, thanks DD. I had to put some blu-kote on my favorite Nn today, that darn randy rooster! There's not many feathers on her head so he got her skin instead. Poor baby.
He's out there crowing his head off, I'm thinking about squirting him with a hose.