What are you feeding her at the moment? Unfortunately I'm not knowledgeable on US feeds, but hopefully someone can come along and let you know which staple feeds would be best. All I am aware of is that you should feed a lab block as well as a muesli mix!
Here is a list of foods which are suitable. It's important to offer a mix of veggies, nuts, seeds and high protein foods to sustain her and the pups. It should be offered daily.