I used to put them in a covered kennel one at a time to figure it out. Didn't do that this time and seemed like everyone was screaming "Come Back!"
But with season coming on, it was like an over night change occurred.
You can't rely on physical appearance, but one morning some of my "girls" were sporting these big floppy waddles (where did THOSE come from?!), standing sideways, charging everything in sight and chasing tails. NOT girls.
I have one named Mia that nannied a brood about 4 weeks younger. The 1st sunny spring day we had, "Mia" went over & beyond to prove she was a he. The name stuck.
I think what stymies me is that the girls are so vocal that it's all you hear. I thought Mia was just quiet bc the Momma to that brood he helped raise picked on him all the time. Now I think the males just don't say much unless they have a reason to, where as the hens will call relentlessly until they have a mate.