If it's only on one leg it could be some kind of scarring. Scaly leg is not something that only happens to one leg.
Otherwise, it does look like scaly leg, and I use Stockholm tar for that but some use Vaseline. It does look though like she's been treated already because it appears the surface is scale-free for the most part, and the old damaged scales coming off is part of most treatments. It's not something you do to them, just something that the body does, like rejecting a damaged fingernail or toenail if its connective layer is damaged enough.