Buckwheat hull pillows are prevalent in Asia, but buckwheat and millet hull pillows haven't really caught on in North America, where feathers, down and polyester fiber fillings are the most common. Hull pillows are readily available at many department stores and online retailers, however, and generally aren't more expensive than high-quality pillows with other types of fillings. They also provide certain advantages over other pillow fillings.
Feather, down, fiber and foam pillows all compress and lose their shape to some degree during use. Buckwheat and millet hulls, in contrast, shift easily, making them more effective at conforming to your head and neck. In addition, if you find your pillow is too thick for the way you prefer to sleep, you can zip it open and take out some of the hulls. Certified-organic buckwheat and millet hull pillows are available, and the substances are good for people concerned about chemicals in certain types of foam and those who choose not to use animal products.
Millet hulls are lighter and smaller than buckwheat hulls. They are round and smooth, while buckwheat hulls are coarse and have irregular shapes. Millet hull pillows thus are lighter, softer and smoother than buckwheat hull pillows. They also are quiet when you move around, while the larger buckwheat hulls make a soft sound you might describe as shuffling or rustling when you shift your head. That's because they hold more air than millet hulls do.
Although the air moving through buckwheat hulls makes a soft noise, this provides better ventilation in the pillow. You might find this keeps your pillow at a more comfortable temperature. Buckwheat hulls also hold their position better than millet hulls do. In addition, buckwheat hulls don't have the light grassy odor that millet hulls do for the first few weeks.