Rabbits fart.
Rabbits are non-ruminant herbivores which means that they eat plant matter. For your pet bunny, this means that they eat hay, pellets made out of hay, fresh grass, and weeds, as well as occasional vegetables or fruit as treats. However, they can also eat very slow-to-digest plant material like twigs or bark.
Those slow-to-digest foods will actually ferment as they travel through the rabbit’s digestive tract, which produces gas.
Rabbits do pass gas or fart because they regularly eat slowly to digest plant-based foods that create gas as they slowly pass through the bunny’s digestive system. That gas must be released in the form of farts for the comfort and health of the bunny.