I bred california red-sided garters for a few years so here's my limited experience input. Most of the babies shed immediately after birth(talking minutes after being born here) and I start offering food within 24 hours. I'd offer a mixture of freshly chopped earthworms and finely chopped f/t pinky mice. The wiggling bits of worm get them over to the feeding station and once they start scarfing food, especially when competition arrives, there's no stopping the frenzy short of a cleaned plate. Providing food daily or every other day, I'd reduce the amount of worm and have most feeding on 100% prepared rodent within a week or two. I noticed a strong competitive drive with these to where raising them in groups simplified things greatly. You only need 1 from each group to make it to the feed station and the rest quickly follow suit.