There can be a number of reasons why your bunny’s poop is smaller than usual. One possibility is that he or she is stressed or anxious. This could lead to smaller poops as a way of conserving energy. Another possibility is that your bunny is feeling sick, and may be eliminating less to avoid adding to his or her illness. If you notice your bunny has been having small poops more often lately, it might be worth contacting your veterinarian to check out his or her health status.