A partition feeder (10) has a multi-rack assembly for holding more than one reserve stack of partitions (14). The partition feeder (10) has a main stack of partitions which is forced against a set of tabs (18) and which has its partitions (14) removed by a selecting apparatus (32). When the main stack has been reduced down past a certain amount, one of the reserve stacks is automatically moved into alignment with the main stack and the partitions (14) in the reserve stack are added to the main stack. The partition feeder (10) has guide rails that are received in notched sides of the partitions, thereby suspending the partitions (14) on the guide rails (12). An inner frame (166), upon which the guide rails (12) are mounted, is adjustably mounted to a middle frame (164) to thereby permit the adjustment of the distance between the guide rails (12). The partition feeder can therefore be easily adjusted for partitions of different sizes.