My guess although I'm certainly no expert so I'd leave it to them but just from what I've seen is...I think they look like girls from what i've seen of others Roosters...and the ones I owned that were roosters although not silkies...they just look girly in the face and feathering...my Roo's looked like Roo's my one silkie always looked girly sounded girly acted girly so by my luck she turned into a girl...yours are beautiful...how old are they that might help as well...since silkies take FOREVER to show what they are unless...they are really obviously one or the other.
When were they hatched? How old are they in the pictures? Silkies tend to take longer then standards and therefore it's about 5 months and up before it's really known what they are. It's a lot of guess work. What's been floating around is a rounded crest (the top knot fuzzy part) is a hen, while a spiky crest is a roo. good luck!