Generally, a young roo will have wispy longer feathers coming out of the back of the crest. You can kinda see them in the first two pics. Other thing is, this silkie looks "roo-ish". There is just a general sweetness to a pullet, and the roos look more "cocky" Also, those are some mighty big feet. Stocky legs and large feet are sure sign of a roo in young silkies.