If your rabbit stops eating for even a day (24 hours) that is a bad sign. If a rabbit's digestive system comes to a standstill they can die very quickly.
When I mean the rabbit isn't eating, I mean that it won't eat anything. Not hay, no pellets, not it's favorite treat or green vegetable. Nothing. If you can get it to eat something, like hay, pineapple, or celery, but it doesn't want its pellets, keep feeding it that and other things like it so the digestive system doesn't completely stop.
Read the article above, that is what this blog is mainly about. Just shared my thoughts on the "not eating" concept.