While rabbits can eat cucumber, they should be three months old before they are offered cucumbers. Vegetables can be useful to rabbits' dental health and can provide useful nutrients.
Begin giving a rabbit one kind of vegetable at a time. Some vegetables may make rabbits sick. A rabbit shouldn't eat cucumbers if the vegetables cause it to have soft stools or diarrhea. Vegetables are good for rabbits' teeth because they require more chewing than hay. Foods that are too easy for a rabbit to chew can cause uneven tooth wear, which can be very painful. Rabbits under 7 months old can eat alfalfa hay; once a rabbit is 7 months old, it can eat grass hay.