In fact, the Georgia Department of Natural Resources recommends that 75% of the seeds in your feeder should be black oil sunflower seeds. You can make it easier for them by providing hulled sunflower seeds or sunflower seed chips. Be aware that without their hulls, hulled sunflower seeds don't stay fresh as long as they would with their shells. Consider supplying only a small quantity of hulled seeds, especially because they are more expensive than sunflower seeds with hulls. You'll want to read up on how to keep squirrels out of your bird feeder.