Mama rabbits usually don't have much of a maternal instinct. They don't spend a lot of time with their babies, but they do feed them. If you don't feel she's feeding them, keep her calm with some pets. Then move her very close to the babies in a position where they can nurse. Babies eat about twice a day, just watch them to make sure they're getting enough nourishment. Bellies should be round, skin pink with no signs of distress. If mama rabbit refuses to feed them, you'll have to set up a schedule so that you can feed them twice daily. Please check the article "Mama Rabbits and Offspring" for information on what to feed, amounts and care.