Eating hay is great - it’s a necessary part of a bunny’s diet - but they should also eat their pellets too. If they have been refusing pellets for over 24 hours, start with why they might be refusing them. Check out the first section with ‘Why has my rabbit stopped eating’. As long as they are eating, there’s no need to panic just yet. It could be something as simple as not liking them. Eating hay and leafy greens is a good sign though.