Yes, take some vaseline and COVER their entire leg with vaseline--really get it in there. This will suffocate the mite that has burrowed under your hens scales. Do it again a week later and then within a fe weeks her old scaled will fall off with fresh, pretty new ones! Also, if she has scaley leg mites, this means she has mites, so I use either Sevin dust or Adam's flea and tick spray!
Sevin is a dust you can buy at walmart or home depot in the lawn and garden sections. Adams flea and tick spray can be bought at walmart in the pet section. If you are using sevin, you put the chicken in a tall bucket and sprinkle the dust all over it--under the wings, on top of the head, neck, tail, and chest. If you are using the Adams spray, you spray 2 good squirts under each wing, neck, tail, chest and top of head. I would also spray the feathered parts of her legs(hips). I have used both on my chickens with no side effects and also treated a chicken with scaley leg mites with the vaseline--if you don't have vaseline, anything non toxic and greasy can be used, like crisco. I use the petrooleum based substances cause it wil stay on for awhile and can't wash off easily, which you want!