I use grinding corn in the grain mix and when I make corn bread. It is cheaper. Mostly I eat popcorn after I pop it Hulled Millet , most people recognize this grain as bird seed, but bird seed is unhulled. Oat Groats are unbroken kernels before they are rolled. Rolled oats are steamed and then smashed between big steel rollers.
Quick oats are rolled flatter than old-fashioned, so they cook faster.
Brown Rice has the bran left on, just like hulled barley. In processing the rice to make it white or polished the bran, the good stuff, is thrown away, or fed to pigs. Whole Rye distinguishes the rye from cracked rye. Many people think they don't like rye because of the caraway seeds that are usually in rye bread. Wheat Hard wheat is used in making bread and pasta.