Thank you. Very well observed. Yes he probably has a bit of scaly leg mites. I'm still in the process of building enough trust so he let's me treat it.
Discussion
Have you handled your birds at night with a headlamp? Its usually far easier and limits stress. Grab him by the legs and hold him like you are carrying a football. His head near your armpit. Its also a good time to access general health, mass, mite or lice loads. Check their cloacal vent area to assess numbers of feather lice.
That's a good idea. I will try that.