Rabbit Digestion 101
Your bunny has more in common with a horse, than a cat....
are vegetarians, and are specially adapted to get the maximum nutrition
out of food that is indigestible to other animals. You may see
your bunny eat wood, dried leaves and straw - don't stop her, she is
doing what comes naturally, and this coarse fiber is very important to
her digestive system.
Hay, grass, and other "large" fiber particles help to keep her digestive system moving. And a moving gut is the key to rabbit digestive health. If your bun stops eating for more than 12 hours, be concerned. If she is still not eating after 24hrs, this should be considered an emergency - take her to a vet that knows rabbits !
Smaller particles are diverted to the cecum, where fermentation helps to break down food which would otherwise be indigestible. From here they are "packaged" in a protective coating, and excreted. You bunny will eat these "cecals", and the food will be properly digested (the second time through). These poos are smaller, wetter, and shinier than her normal poo, and you probably won't see them often, as she will eat directly from the source !
If you see cecals, your bunny is probably getting too much nutrition from her food, and doesn't need to get the extra boost. This is not a problem in the short term, but if you notice it continuing then you need to see your vet to check for an underlying problem.
If a bunny ignores her cecals for any length of time, the bacteria in her cecum can become unbalanced, which can lead to further problems.