A truck for shredding and mixing products for zootechnical use which comprises, on a self-propelled or towed wheeled chassis, a container (12) that is substantially shaped like an inverted frustum, is open at the top, and contains a rotating scroll (13) that has a vertical axis and an external profile (14) that lies on an ideal substantially conical surface, shredding cutters being fitted at the profile. Vertically arranged countercutters (17), shaped substantially like a circular sector, are pivoted about their respective vertices (16) to the wall of the container (12) in substantially radial positions and can be inserted and extracted through appropriate slots. The truck is characterized in that the countercutters (17) are arranged so that the vertex (16) of each one is in a substantially median region of the wall and so that they extend downward until they affect the lower part of the wall.