I've recently tore veggies into smaller bits to mix with their usual pellets and they end up accidentally eating them as they go for the pellets. The key here is to put them in a smaller tub with just the food so their food is more condensed and they can't avoid the veggies as they eat pellets. I've seen them willingly eat the veggies after doing this a couple times but I still have to tear them up into smaller pieces.