An apparatus is provided for pre-conditioning the materials in a bulk bag (4) to effect easier unloading of the material. A frame (10) is provided with an open space for receiving the bulk bag. A series of spaced-apart, opposing breaker bars are provided for automating thrusting against the sides of the bags to break up compacted material. The bars preferably have an angled profile. Parallel pairs of opposing horizontal bars (30) are provided, evenly spaced from the bottom; and preferably a single opposing vertical pair (40) is provided on the opposite sides. The pairs of bars are operated, by thrusting into the sides of the bag, in a timed sequence, to effect break up of the material. Additionally, a series of bars (20) may be provided on the bottom of the frame (14), such that a break up effect is achieved against the material residing in the bottom of the bag.