Doggylover, personally I wouldn't do it. I have known some vets to recommend a very little bit of cottage cheese mixed with other ingredients for specific problems, but never as part of a regular diet. Any milk products for dogs, in general, is not a good idea. They don't digest it well.
Believe it or not, there really are some dogs who don't inhale their food as soon as it is served! LOL. They will just pick at it all day long if allowed to. You seem to have one of those. If her weight appears good, then please don't worry. She is eating what she requires to sustain herself. If you are feeding her more than 2 cups of dry chow a day, then you are feeding her too much and that is why she is picking at her food. I don't know what your routine is, but you should be feeding her 1 cup of chow in the morning, and 1 cup in the late afternoon/early evening, depending on your schedule. Dogs generally are hungrier at the end of the day after they have been active, then in the morning after they wake up.