The grinding or rolling of grain can produce acceptable swine feeds if the mills are operated correctly. However, there are differences between these two types of mills in their processing capacities. Roller mills can process twice the amount of product as a hammer mill. Roller mills can also produce uniform particle sizes, which can result in improved digestibility. However, roller mills require more upkeep to maintain the correct setting on the roller gaps, whereas hammer mills require less monitoring. Roller mills have a greater difficulty in processing small grain seeds to the correct particle size, and those grains that have a hard seed coat (e.g., sorghum) should always be ground.
Hammer mills have an advantage in flexi-bility of use. Because of their pulverizing nature, hammer mills can effectively process high-fiber feed components at a more uniform particle size.