The mama cat is nursing her babies. Maybe she is not feral, because she is letting us approach her now. We left out cat food, but she didn't eat all day, so PS and DH were able to hand fed her some of the kitten formula and some lunch meat. Not ideal, but nursing moms need to stay nourished. We are also trying to supplement the babies in case mom isn't making enough milk. We are thrilled that all of the babies have survived so far.
I talked to the lady who ran the cat shelter that we fostered for. Her shelter is now defunct, but she said that she could give us any supplies that we needed and help us find homes when they are weaned. She also has a cost efficient resourced for having them neutered.
So, if anybody out there wants a kitten, I have 6 and I'd be happy to overnight one (or two or three) to you!