If this were my dog, I would want to find out what is causing her excessive licking before I started supplements. Is it just her feet, or does she have recurrent ear infections? Is she itching and scratching other parts of her body excessively?
Your dog may be allergic to something in the environment, maybe licking her feet out of boredom, or may even be allergic to that Hills diet. (Read the label.)
If you are not able to find out what is causing her excessive licking, and just want to try a supplement, I can only recommend some natural sources. Honey, when it is harvested locally, will contain many allergens that the dog is allergic to and will act like allergy shots. If your dog is inside all of the time, and the allergies are not seasonal, you can try to reduce the allergens she is exposed to: https://pethelpful.com/dogs/tips-to-make-an-allerg...
If it is only her feet, you can also try to soak them in Epsom salts or wipe them with apple cider vinegar. (As long as you do not use too much it is not going to hurt her to lick the feet, but if you are soaking them in Epsom salts be sure to wipe them clean after.)