It looks like scaly leg mites.  Those bumps look like cornification and hypertrophy that can result from it.  You can treat it by soaking the chicken's legs in oil--castor oil, vaseline, cooking oil, coconut oil.  I have heard good things about castor oil in that it doesn't need to be applied that often.  Before the oil treatment you might want to soak her legs in warm soapy water and use an old toothbrush to scrub the legs a bit and soften them.