Babies this young should not have their pellets rationed -- they need unlimited pellets and hay for them to grow. Their pellets also contain calcium and other nutrients they especially need at this time in their life (including vitamin C).
Just keep putting vegetables in their enclosure, and try with small amounts, 2-3 times a day. Rotate out through things that have a lot of odor, especially things like cilantro, parsley, basil, watermelon, cantelope, and strawberries. With stalky vegetables like cilantro and parsley, you can handfeed them by poking the stalk into the side of their mouth past their teeth to get them to start chewing.
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry