From what I read, rabbits eat their droppings. That is not the dried out pellets which presumably are the result of a second trip through the rabbit's gut, but the cecotropes which are moist and just predigested hay/grass which has gone through the rabbit's gut once. In theory, because the cecotropes are fermented they would be "less worse" to eat than the dried out pellets, the latter being the toxic remains gotten rid of by the body. That said, we humans are not designed to eat grass or hay, however fermented, and eating what has just gone through a rabbit's gut is just not palatable. Plus, the rabbit needs this food.