Welcome to BYC. Two of the most common foot problems are bumblefoot and scaly leg mites. Without a picture any guess would be sheer conjecture. Do a forum search on each problem and see if that is what she is dealing with. There are several threads on treating both conditions. Good luck.
That looks like scaly leg mites. Rub you hen's feet with vasaline or a cooking oil and it will smother them and treat the skin at the same time. If you do this at night you will have a less stressful time, as they are so much more docile then. Do this once a week until symptoms subside.