Help sexing Rhode Island Red/Black Marans

[tideluva]

So I got my first chickens from my uncle who has a plethora of varieties of chickens. He gave me 9 (one Dominicker, and the rest Black Maran/Rhode Island Red).
As time has passed I noticed that the Black and Reds appear to have some mix in them and of course these breeds are kept together at his house.
He will let me swap out the roosters with hens at his house but being new I am unsure which are which. Please help a newbie!

 

[Michael OShay]

So I got my first chickens from my uncle who has a plethora of varieties of chickens. He gave me 9 (one Dominicker, and the rest Black Maran/Rhode Island Red).
As time has passed I noticed that the Black and Reds appear to have some mix in them and of course these breeds are kept together at his house.
He will let me swap out the roosters with hens at his house but being new I am unsure which are which. Please help a newbie!
All of the bird in this picture look like cockerels except the one Marans in the center and the one RIR on the right

All of the birds in this picture look like cockerels except the one Marans on the right and the one RIR on the right.

All of the birds in this picture look like cockerels except the one Marans in the center and the one RIR on the right.

 

[donrae]

Agree with Michael. Lots of cockerels there.

 

[tideluva]

I seem to have "the gift". After picking 9, six are roosters. Thank you all for your help!

 

[Wyandottes7]

Agree with Michael. Lots of cockerels there.

x2

 

[BantamLover21]

Agree with Michael. Lots of cockerels there.

x3