I have an EE that has slovenly eating habits and she has a perpetually crusted beard. The other chickens try to help her out by cleaning her beard, but, alas, she only layers on more as she eats again, and for most of the year, has a scant beard from all the attempted "cleaning" by her mates.
I've tried washing her beard, but, aside from her hating the procedure, it does little good since the stuff hardens like cement and is impervious to soap and water.
Therefore, I can be of little help in this matter, being the keeper of such a chicken myself and being helpless to figure out what to do about such a slob.