The raw material must be crushed or ground to a given particle size, in line with the subsequent cooking or hydrolysis procedure. Depending on the initial size of the product, it may be necessary to use pre-crushers, as in the case of whole animals. There are different types of pre-crushers, crushers, and grinders, according to the type of product to be crushed and the particle size required in the process. The equipment can feature either high or low rotation, with one or two shafts and different claw sizes.