Not too sure on this ones age, but I think s/he’s a black Maran
With that color pattern your cockerel would be a Black Copper Marans (BCM) or a Wheaten Marans. We need to see a full side shot so that we can see his wing. If the Wing Bay is black then he is a BCM and if it is Brown (or Rust colored) then he is a Wheaten. Black Marans are solid black. Do you have any Marans Pullets?