Hard to see the ear, if you can get more photos of her face and how she stands that would be good.
A crusty ear may be ear canker or possibly mites or infection.
I agree, it looks like impacted feather follicles, you may want to pull one out and see if there's pus.
At the age of 12, I'd be hesitant to do anything drastic, but if you can express any pus out, it may help her heal a bit.
A chronic skin condition could be Marek's. Even though she's quite old, if she's had skin issues all her life, this may be the cause.