The crushing of the raw material input for animal feed powder is carried out by a crusher machine with a rotary speed which can crush the particles into smaller pieces. Hammer mill is a crushing machine for changing the input of animal feed particles into smaller particles or powder. One part of the hammer mill machine in crushing particles of raw materials is the hammer mill blade, each hammer mill blade shape must be different in the resulting the particle size results. The purpose of this research is to make a prediction model of the particle size seen by the hammer mill blade shape. The particle size prediction model uses the Discrete Element Method (DEM) with Rocky DEM software, which is compared with the prototype results in the field as simulation validation. The smaller the particle size for animal feed, the better the digestion of the animal, but the larger the particle size of animal feed, the more difficult it is for livestock to digest their food and even damage their digestive system. Based on the results of DEM, the particle size resulting from the crushing process of organic waste from coffee skin is 0.26 mm, coconut shells is 0.30 mm and oil palms is 0.30 mm. The simulation results are similar to the results of the collision of the prototype in the field, which is less than 0.5 mm through the screening process by the screening section.