A couple of members here, including myself, just feed Oxbow adult rat food. That should be enough protein for the babies.
Too much protein in rats can cause health issues, I believe. A couple of senior members made a post about the China study for rat nutrition.
yes, but the rat blocks provide more protein then adult rats (10%) require
plus they will get protein from eating vegs
If you feel the need to supplement their diet, feed organic soy infant formula thickened with baby cereal,
but they should be fine with a good quality block (oxbow or Harlan 2014) and a variety of daily vegs