Feather mites are different from scaly leg mites which I don't think are visible at a glance. I used Castor Oil massaged into the skin to suffocate them. Works good and not as messy as vaseline for example.It looked like one scale was, we looked all over her today for mites didn't see any. The Feed store recommended putting down Diatomaceous Earth for them to dust bath in.
The second to last picture you uploaded....those legs/feet look pretty swollen.