What can cause diarrhoea in rabbits?

There is a difference between diarrhoea and loose/sticky stool.

Diarrhoea is watery and comes acutely. It is usually caused by bacterial, viral or parasitic infections. Emergency veterinary care should be sought.

Loose stools are often sticky or clumpy. They can be caused by poor/inappropriate diet, stress, obesity and back or limb pain. Veterinary care should be sought. Loose stools can result in bloat, impacted gut, skin infections, and fly strike.

Rabbits pass cecotrophs in addition to normal faecal droppings. Caecotrophs are moist, and softer than normal droppings. They also tend to have a slightly slimy surface. Rabbits eat these. If your rabbit is unable to reach or eat its caecotrophs (due to for example obesity or back/limb pain) they will cake and get stuck to your rabbit’s bottom.