I hatched out nine E.E/Silkie crosses, this year and I though Silkies were a challange to sex. I didn't figure out their gender until a few months into the game, not long before they started to crow, as the roosters finally developed the curved black tails. So I would give her/him more time. Of course in my situation had eight roosters, and 1 hen.
But the tail does look straight so far, so maybe you will have a little girl! I have heard that you can sex Silkie crosses by skin color, but I didn't find that to work with my super dark skinned E.Es.
Good luck,
RhodeRunner... according to that article I have a girl but........ it's getting spikes in the crest... I'll get a pick here later this evening at 8 weeks old...
Vent sexing? Uhmm.... I checked but have NO idea what to look for!!