A conveyor having a conveyance structure, belt, and gas manifold. The gas manifold disposed within or on an exterior portion of the structure. The gas manifold having one or more manifold outlet ports to dry, condition, or treat a metered stream of seed within the conveyor. The manifold may be operably connected to a recirculating air system providing the vacuum source and pressurized air source of atmospheric or conditioned air. A filter and vacuum port may extract debris or humidity from the metered stream of seed within the conveyor. A plurality of mixing baffles may be longitudinally spaced apart through the conveyor in a laterally alternating manner to mix the metered stream of seed. The conveyor may be used to transfer, mix, dry, condition and treat the metered stream of seed between multiple stages of treatment.