White growth on chickens leg

[Bjararydaren]

My dwarf silkie chickens have had some white leg growth for a while now. They're aren't noticing it themselves and it doesn't bother them but it worrys me that I have no clue what it actually is. I have searched the internet and now I'm asking here.

What is it?

Is it harmful?

If so how do I treat it?

Here's some pictures

 

[sourland]

They have scaly leg mites. Do an on site search on 'scaly leg mites' for more information and treatment.

 

[Bjararydaren]

But all cases of scaly leg mites I've seen have never included that white leg growth. How can this be?