It is an uncontested fact that rabbits are physically incapable of vomiting. Rabbit health is primarily dependent on digestion, moving large quantities of low-value food from one end to the other, sometimes making the passage more than once.
Occasionally, rabbits suffer from bloat, which comes from a buildup of gas in the stomach. If gas is created in the intestines rather than the stomach, are rabbits able to expel it or will it migrate to the stomach?
While I did not find any reliable references that clearly put it as boldly as the question, there can be little doubt that rabbits do fart.
Lets begin by looking at a rabbits digestive track.
Image from Wikimedia Commons
Notice that the stomach is very early in the digestive track, this is the usual problem area noted for gas accumulation in bloat. Then follows the small intestine, and the at the beginning of the large intestine is the caecum/cecum.
The rabbit cecum is much more developed than in most other animals. Food products stop in the cecum and ferment (Nutritional Ecology of the Ruminant By Peter J. Van Soest Page 67) generally staying there until night, with gas as one of the products of fermentation. The rabbit cecum is described in veterinary imaging references as a "large gas chamber that contains a mixture of food and gas" (Diagnostic Imaging of Exotic Pets: Birds, Small Mammals, Reptiles By Maria-Elisabeth Krautwald-Junghanns, Michael Pees, Sven Reese, Thomas Tully), which is particularly noted for it's difficulty to image (i.e. Xray, etc)
Disruption of motility of the cecum is called "cecolith" and can be diagnosed by an increase in the amount of gas in the cecum. (Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery By Katherine Quesenberry, James W. Carpenter).
So we know that gas is produced in the cecum, and if there is decreased motility the gas increases, the logical conclusion is that in the healthy rabbit the gas continues through the colon, and is expelled from the anus. At this point there can be little doubt that healthy rabbits fart.
One of the recognized treatments for gas in rabbits is Simethicone, an anti-foaming agent that helps in the passing of gas (Rabbit Health in the 21st Century: A Guide for Bunny Parents By Kathy Smith). Note that gas accumulation in rabbits is potentially (often) fatal, so prevention of accumulation is extremely important.
Rabbits can definitely fart
The gas will need to be expelled somewhere, and it seems likely that if they can poop that they'll be able to fart also.
According to many websites, the jury seems to be out on whether it's common for rabbits to burp (and whether or not this is indicative of gastrointestinal problems.) Intuitively, because rabbits can't vomit, they'll probably have some difficulty burping as well.
