When Leo first joined us, we understood from the rescue group that he was not eating any fresh greens or dried grasses. I believe he was offered things like romaine. Well, he ate romaine once since he's been here -- scarfed down a small bowl of it his first morning here -- but hasn't eaten it since.
Happily, he has eaten other greens with regularity. He likes red radishes and their greens (not the white radishes and their greens, though), turnip greens, mustard greens, arugala, dandelion greens, pea shoots...perhaps a few other things that I can't remember. We try different things with him, including whatever we hand on hand or get in our organic produce bag.
A rabbit's diet should be made up of good quality pellets, fresh hay (alfalfa, timothy or oat), water and fresh vegetables. Anything beyond that is a "treat" and should be given in limited quantities.
While we're very pleased that he's eating greens, I see from their suggested vegetables list that we've a long way to go in terms of getting a variety of greens into him. I just noticed this bit about variety and vitamin A:
Select at least three kinds of vegetables daily. A variety is necessary in order to obtain the necessary nutrients, with one each day that contains Vitamin A, indicated by an *. Add one vegetable to the diet at a time.
Twice a day we offer him a small bowl of greens, sometimes with veggies and/or fruit. Sometimes we offer him a little fruit later, after he's eaten his veggies. Kind of like dessert. And he eats it like dessert, i.e., he'll it first if it's served with his greens and veggies.
According to the HRS, fruit is a treat and should be served sparingly: "daily ration no more than 2 oz. (2 TBL) per 6 lbs. body weight". At 3.5 lb. he doesn't qualify for much fruit per day.
Here's a typical portion: