What and how much are you feeding at each serving ? Have you tried any toppers? You can add fish oil, coconut oil, steamed vegi, boiled beef, cottage cheese, shredded cheese, lowfat sodium free beef broth, lowfat sodium free chicken broth. She could just not like her kibbles. Some dogs just get bored with their food.
She could also be not feeling well. Try the toppers and if she still wont eat you might want to get her blood and thyroid checked.