LOL my piggies eat treats all the time you know why? Because there's no vegetable they would leave behind,
there's no basic or regular food, everything's a treat to them..at least that's what it seems for there's nothing they would turn around and look away. You can do what I did, I made myself a list of the most rich and nutritive vegetables (link to one of the friend sites I think it was guinealynx) and then I pasted it on the fridge so I remember everything they like ...everytime I'm having a fruit for after lunch, they start crying mostly begging to me and Im' in the kitchen but they are in the bedroom! what a nose..so I have to go and share ^^
Good luck