Foot Stained?

[Aloysius]

It appears that my Quaker Parrot Shiloh has a stain on her foot. I went to my local bird shop, and I asked them about it and they thought it was probably just stained from food because there was some orange coloration, but when I took her home and gave her a bath, and washed her foot off, while the orange went away, the stain was still there. Most of her left foot is much lighter than it usually is. It looks almost purple instead of black. She also occasionally attacks her foot randomly while preening. The owner of the bird shop said that it's probably a nervous behavior, and that nervous behaviors and self-mutilation are common in Quakers(which I was already aware of), and that it was not much to worry about. Does anyone have anything like this? Please give me your input.

[Michael]

If it definitely isn't a stain, it could be a symptom of bumble foot or foot sores. Sometimes it's caused my poor perch variety and they get sore (like getting a blister from bad shoes) but sometimes it's from a disease. Posting a picture might help but regardless, I'd reassess your perch layouts just in case.