You aren't showing the TRUE gender telling part which is saddle feathers on most breeds by the stated age..
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According to the development seen along with stated age.. a boy would have started looking like that closer to 8 weeks and
I'm going with pullet.. getting her hormones.. *may* start laying before her sisters.. about another month-ish in my experience.
Chickens don't read our rule books or care what they say!
My friend had a rooster not crow until 18 months, and has several older hens with full length spurs. One of my hens started crowing when she was two years old.. yes she was the head hen but no it wasn't due to the absence of a rooster... AND some roosters like Seabright are hen feathered roosters!