When they're a bit older, limiting pellets will help but they're so young that I would just keep trying. Try different types of veggies and herbs. You can also try different types and brands of hay...the fresher, the better. See if maybe they'll eat flowers and grass from outside.
How old are they again? Is there a way they could see an adult eat? I think they'll try veggies eventually, might just take some patience. You could try drying some veggies, sometimes they prefer that.
How old are they again? Is there a way they could see an adult eat? I think they'll try veggies eventually, might just take some patience. You could try drying some veggies, sometimes they prefer that.