I see what you mean about the "streamers," and agree that it could be a male. Mistakes can happen. But, it doesn't hurt to keep it for a month to see what develops. Call it a male for now & if it turns out to be a female, it will be a happy surprise.This 12 week old Silkie was sexed as a pullet and sold to me but pretty sure it's a roo. Its got streamers I think and a single comb (not the typical comb) plus acts a bit like a roo, always walking around while the other pullets sun bathe and not paying down with them. View attachment 1093441 View attachment 1093442
I thought mine was a male b/c of the pointy crest & wider comb.



It's still named Zander, but it looks like a female now. (about 15 wks old)
Another thing to look for is slightly darker color on the wing's shoulders - on males.