Which symptom would most likely lead to an urgent veterinary consultation?

Dullness and lethargy are significant symptoms that often indicate an underlying health issue in rabbits. Rabbits are generally active and alert animals; any noticeable change in their energy levels can suggest that they are experiencing pain, distress, or illness. Lethargy, in particular, could be associated with various serious conditions, such as gastrointestinal stasis, infections, or systemic diseases, which require prompt veterinary attention.

In contrast, regular hopping is part of a rabbit's normal behavior, and playing with toys indicates they are engaged and healthy. Eating habits can fluctuate for various non-urgent reasons; however, any drastic changes should still be monitored but don't warrant immediate attention like signs of lethargy. Therefore, dullness and lethargy stand out as critical symptoms that should prompt urgent consultation with a veterinarian.