No, carrots are very high in sugar and should not make up the bulk of a rabbit's diet. If they are given as a meal, it must be in moderation, and I mean moderation, only feed them as a meal twice a month at most. They are better used as an occassional treat, as they are like chocolate to a bunny. What you should feed them lots of is hay, specifically timothy hay. They also need fresh fruits and vegetables like cabbage and blueberries (which my bunny, Snowball, LOVES). In addition, when you make changes to their diet, do it slowly. Rapid changes can cause their intestinal flora to change dramatically and most likely lead to death. I learned a lot of this from personal experience, but I did do a lot of research before getting my bunny, which sadly few people do these days and the bunnies die because the owners have no idea how to care for them. I would like to say to those owners that this is what they get for not thinking ahead.