A spreader assembly to distribute materials on a ground surface, including a container to hold the materials, a frame affixed to the container, a beater assembly supported by the frame that receives the materials from the container and processes the materials to obtain processed materials, and a spinner assembly that receives the processed materials and expulses the processed materials from the frame onto the ground surface. The beater assembly includes a pair of rotating elements that blends the materials to produce the processed materials, and a deflector located between the pair of rotating elements configured to prevent the formation of agglomerates in the processed materials.