In this video from rabbit YouTuber One More Please, Pipkin the bunny eats a stick of crunchy celery, carefully recorded with an up-close microphone. Pipkin’s owner notes, “Is celery safe for rabbits to eat? Yes, it is! Like all foods though, except the rabbit’s beloved hay, moderation is key.” From Rabbits.org:
Leafy Greens: These foods should make up about 75% of the fresh portion of your rabbit’s diet (about 1 packed cup per 2 lbs of body weight per day).
Non-leafy vegetables: These should be no more than about 15 % of the diet (About 1 tablespoon per 2 lbs of body weight per day).
Fruits: These should be no more than 10% of the diet (about 1 teaspoon per 2 lbs of body weight per day). NOTE: unless otherwise stated it is more nutritious to leave the skin on the fruit (particularly if organic), just wash thoroughly. IF you are in doubt about the source of the fruit and you are concerned about chemicals in the skin, then remove it.
In this video, Pipkin eats a long apple peel string without stopping: