Sunflower seeds are a great source of natural oil (38-50% oil; Wan et. al. 1979) that improves the health of rabbits. However their diet should not contain more than 20% sunflower seeds (BALOGUN and ETUKUDE 1991) and needs to be based upon hay that is fortified with chelated minerals and balanced with natural vitamins.
Baby rabbits need a high energy food that is low in starch but high in fat. Adult pet rabbits will be healthier eating a low energy pet rabbit food that is grain-free and soy-free. Following these feeding recommendations will provide the nutrients that rabbits need to support optimal health. Balance is the key!
So can rabbits eat sunflower seeds? Yes they can if they are a part of a balanced diet.
BALOGUN T. F., ETUKUDE U. W. , 1991. Undecorticated, full-fat sunflower seeds in the diet of rabbits. Journal of Applied Rabbit Research 14:101-104.
Wan P.J., Baker G.W., Clark S.P., Matlock S.W. 1979. Characteristics of Sunflower Seed and Meal. Cereal Chem. 56:352-355