Rabbits do get vitamins and minerals from their pellets. At 5 months of age, you can start limiting pellets and feed them in amounts according to her weight. A medium sized rabbit (5 – 7 pounds) should only get around 1/4 cup of pellets a day. Some people do eliminate pellets from an adult rabbit’s diet or only give them a tablespoon of pellets a day, but to make up for a pelletless diet, one is supposed to give a rabbit a variety of 15 different greens/veggies a day, which could be difficult.
It’s very possible that with the greens in her diet, she doesn’t want the pellets as much. But any time a rabbit stops or limits eating of a certain food, you need to keep a watch on them and make sure that they aren’t having any dental issues. Keep an eye on her. If you see any other signs of possible dental issues – drooling, food falling out of her mouth, then take her to the vet. It’s likely that the new greens are keeping her happy and full and the reason why she is eating less pellets, but just keep a watch on her.