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.
fill a bucket up with kerosene and iodine. That will get rid of the bumblefoot in a couple days. My uncle raises poultry and he taught me this.
Howdy from Kansas, 987mitch, and ! Great to have you aboard. Sorry but I have no medical advice for you. Hope you get a handle on it.
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.