Urine

"Normal rabbit urine varies in colour from yellow to orange, brown or red depending on nutrition and hydration status and may be influenced by medication."

"The normal color of urine from rabbits is yellow. Sometimes the urine can become red, pink, brown, or orange. This condition, often simply called 'red urine,' can occur in healthy rabbits as well as those who are ill." Causes can be: plant pigments, antibiotics, stress, dehydration, blood, and bilirubin or urobilinogen.