A rabbit may stop eating for a variety of reasons, and none of them are good. First, there may be something wrong with the rabbit's teeth, such as malocclusion or chipped teeth. Malcclusion teeth may be clipped, but consult a vet. Another serious problem could be a hairball. Rabbits cannot cough up hairballs like cats can. Hairballs are most common in long haired breeds but can occur with any rabbit. If this is the problem, feed lots of timothy (not alfalfa) hay, give papaya tablets or pineapple juice, and feed bird seed (this helps with digestion). Another, possibly less serious, reason is a change in diet or stress. If you have suddenly changed foods, added hay, or something is added to the area that upsets the rabbit, it may stop eating. Try to ease the rabbit into its new diet, or remove the stressor. I've had rabbits that wouldnt eat pellets because they enjoyed the hay too much.
