An oscillatory feeder operable to convey a flowable solid material has a tubular body and a displaceable body segment. The tubular body has at least one first end, at least one second end opposite the first end and a displaceable body segment between the first and second ends. The displaceable body segment has a first fixable location positionable at a first fixed location and a second fixable location positionable at a second fixed location. The actuator is attached to the displaceable body segment and controllable to cause selected displacement of the body segment and attached actuator and corresponding selected flow of solid material within the displaceable body segment in a feed direction extending generally from the first end to the second end.