My understanding is if a bird doesn't show frizzles it does not carry the gene as it is a dominant gene. Can you post pics of all birds in question, including the chicks?
I've been reading about the frizzle modifier gene, though I'm still not entirely sure how it works but basically what I am reading is that it is a completely separate gene that "dilutes" the frizzle gene. This is what give you the frizzled silkies, the ones with silkie feathering. I'm wondering if it is possible she may have this and it is hiding the frizzle very well?