Wow, I've got it easy - so far! Here's a picture of Peckerhead (named because the other three pecked her head, get it? bwaa ha ha ha!). She's back to normal already but you're right, it's kinda freaky to see the first time!
I have a blue orp. hen who is really bad right now, but has done a great job keeping some top feathers to hide her hideousness. If you touch her though, she's nothing but feather quills. She almost looks like a porcupine if you lift up her mask.