A mixer particularly suited for use in mixing fluid materials, such as feed for livestock, characterized by a portable, elongated shell having an open top, for therein receiving materials to be mixed, a side discharge port, for discharging mixed materials, and a plurality of parallel augers adapted simultaneously to advance the materials in opposite directions for transporting and incidentally mixing the materials. A particular feature of the mixer resides in an agitator conforming to a rotatable paddle wheel operatively affixed to one of the augers, for mixing the materials received within the shell, adapted to avoid the effects of substantially immovable obstructions encountered by the agitator as it is driven in operative rotation.