My 3.5 month old Barred Rock is developing dark burnt orange spots in feathers

[SilkySilkie]

maybe you got the breed wrong?

 

[BigBlueHen53]

Here is my golden cuckoo maran pullet. Sorry, you can’t really see the orange-brown bits but they’re there.

View attachment 2828445

I see it. She's pretty! Kinda like chocolate streaks ....