Mixed Orpington Pen

[Beachin]

That looks quite a bit like some of the chicks in this thread, that are a cross of Buff Orpington and Barred Rock:
https://www.backyardchickens.com/threads/buff-orpington-plymouth-rock-cross.319500/

Barred Rocks are genetically "black" chickens, just like your rooster, so crossing with a Buff Orpington gives some chicks that look the same (in that thread, daughters of a Buff Orpington rooster and a Barred Rock hen) and some that are different (ones that show the white barring are obviously very different-looking than yours!)

Thank you very much for sharing photos-- it is nice to see the results of the crosses

Very cool! They have the same "mask", too. Thanks for sharing!