An improved, dual-shaft preconditioner (10, 70, 102) is provided having independent drive mechanism (18, 20, 78, 80) operatively coupled with a corresponding preconditioner shaft (14, 16, 74, 76, 106, 108) and permitting selective rotation of the shafts (14, 16, 74, 76, 106, 108) at rotational speeds and directions independent of each other. Preferably, the speed differential between the shafts (14, 16, 74, 76, 106, 108) is at least about 5:1. The mechanisms (18, 20, 78, 80) are operatively coupled with a digital control device (60) to allow rotational speed and direction control. Preferably, the preconditioner (10, 70, 102) is supported on load cells (62, 100) also coupled with control device (60) to permit on-the-go changes in material retention time within the preconditioner (10, 70, 102). The preconditioner (10, 70, 102) is particularly useful for the preconditioning and partial gelatinization of starch-bearing feed or food materials, to an extent to achieve at least about 50% cook in the preconditioned feed or food materials.