Abstract: A tub for grinding livestock feed on a rotary cutter. The tub has a rotating circular sidewall and two spaced apart, inwardly facing, deflecting baffles that are pivotably mounted to the sidewall and pivoted in unison by an arcuate arm spring-biased to the sidewall. The arm may slide from a first position in which it can be held by a stop, to a second position upon release of the stop. When the arm is in first position, the baffles are held along the inner wall so as to free the center of the tub for top-loading livestock feed. Upon release of the stop, the arm is biased toward the second position where the baffles extend toward the center of the tub following the contour of the livestock diminishing in size as it is shredded by the rotary cutter. The baffles may have a spring-biased swingable lower portion that swings backward upon encountering obstacles in the tub.