Quote:
Cool pictures. I like the "quarterback" black stripe under that cockerel's eye.
They look like they have wheaten and some kind of black restriction in them. If you're getting blues from putting your roo over black hens, then he's definitely got the double blue splash genes. And single factor barring if you're getting some barred and some solid blues.
True mottling is actually a white tip on a darker feather, on each feather. Your chicks look like they have black restriction genes, either Darkbrown or Columbian. I would guess Db, I have a cockerel with similar lighter pattern on his head and breast but is darker on his back and tail, who carries Db. He's gold based though, so his head and breast are barred buff. He is a birchen x wheaten barnyard mix.
Do you have both cockerels and pullets in the mottled color? You could try crossing them later and see what comes out. I'd guess that you'd have more white and less black.