I have had some Silkies that, due to the heavy crest, failed to thrive. I caught it soon enough and trimmed the crest. It was like a whole new chicken evolved. When they can't see, and many can not, they don't eat properly and fail to move about as they should. Caged birds are not so affected, but my Silkies live in a large run just like all the other birds here. Clipping the Crest is standard procedure for many I have. If you are interested in showing then they really should be confined to keep the feathers nice and so they are more able to cope with their limited view.