Black on Buff Orpington’s Tail Feathers?

[homesteadmama8]

Hey all! I have a mix of breeds, all 18 weeks old (Australorps, barred rocks, buff orpingtons) my orpingtons have black on their tail feathers (photos below)

Mites? Disease?
I checked and didn’t see any mites or bugs on them and I use the deep litter system for their coop so I can’t put DE in there, but it seems clean…what is going on? The rest of my flock doesn’t have any discoloration on the tails (but they’re also darker breeds) could it just be the breeding? I got them from mypetchicken.

 

[Tookie]

I've had this on some of my hens too, I don't know what it is though. Curious to find out.

 

[Katynova]

I've had this on some of my hens too, I don't know what it is though. Curious to find out.

I have 4 Buff Orpington's one has the black on her tail feathers. I have had them for a year…. She is fine.

 

[Lacy Duckwing]

It's leakage. Or they're not pure. They are Hatchery, not American, so they're not Show Quality.

 

[homesteadmama8]

It's leakage. Or they're not pure. They are Hatchery, not American, so they're not Show Quality.

Thank you for the response. I looked up what leakage means and all makes sense now. I only want them for eggs anyways, so I’m OK with them not being showed quality. Just glad that it doesn’t mean anything unhealthy is going on!