Acorns, which are a good source of nutrients for wildlife, are produced by oak trees. Acorns, on the other hand, are not a good dietary option for rabbits. While they may love nibbling on the odd acorn, tannins in acorns can make them unwell. Acorns are not the only healthy choice that rabbits may enjoy as treats. Fresh vegetables, sliced fruit, and specially designed rabbit snacks are all terrific possibilities.