I've got a couple of very fluffy butty SL and GL wyandottes, and they have no problem with poopy butts so far. My barred rocks seem to have a bit of an issue with this, but it doesn't cause any problems. Occasionally I'll see one with a klingon, but it always comes off in the dust bath.
I haver silver-laced and buff-laced polish, and a white one, and I have no problems with them, except they're half blind and need their crests trimmed occasionally so they can get around. My buff doesn't have as much crest as the other two, so she's never needed a haircut, but she isn't as cute, either. Because of their large crests hanging over their eyes, they're prone to hawks and other predators. I haven't lost any yet, though.