I would cut the corn or greatly limit it to 1 small treat every week or so.
I've never had Silkies, but have done some reading about them from time to time. I'm on the fence about them. I'd love to have some for their brooding qualities, but feathered feet just seem like a real pain to deal...
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Yes, Silkies especially can suffer neurological damage when attacked and have head trauma. They have a hole in their skull, so a sharp peck to the head can cause problems.
I'd focus on her eating a nutritionally balanced poultry feed. An all flock type feed or chick starter...