Crest looks funny on polish chicken

[blahdi]

We have two female polish crested chickens living together. One of them, her feathers on her crest are looking funny- half of them are brownish instead of white, and arent looking so "cresty". I don't know how to describe it exactly, but you can see her skin through her feathers, and you didnt used to be able to see that.
Is this a sickness, or just something that happens sometimes?
Anything to do about it?

 

[Karlachix]

Could she be molting? Or maybe another chicken has been picking at her feathers?

 

[call ducks]

do you have pics