Silkies carry the rose comb gene; many also carry the pea comb gene. This particular bird does not, it could have lot it in the cross (indicating that the silkie parent either did not carry pea, or only had one copy, and did not pass that one on. This does not look like the ones I have had...
I agree with LilPeeps and Dustin Biery. Crossed to a crested breed the crest would be significantly larger/fuller. Same for foot feathering.
Also, the OP says she lays a white egg--that pretty much rules out a cross with anything that does not.