Do Only Pullets Trill?

[VintageLilFarm]

Just one bird in my juvenile quartet trills. It's the black one with the gold, that is nearly 9 wks old.

View attachment 1338994

I'm hoping it's because she's a girl, lol. Two of the four are definitely cockerels. Thoughts on trilling, and if it's gender related at 8-12 weeks old?
(I tried to post a recording, but it doesn't look like I can post recordings here.)

 

[oldhenlikesdogs]

Can't view your photo. Both sexes make those vocalizations.

 

[Crazy for Chickens!]

Can you hit Upload File, and put your pic directly o this post? We can't see the photo.