An agricultural planting machine includes a seed meter configured to meter seed, a transport mechanism configured to transport the seed to a discharge location, and a loader assembly. The loader assembly includes an element having an actuating surface, a hub configured to rotate relative to the actuating surface, and a compartment supported on the hub and configured to receive the seed from the seed meter and to eject the seed into the transport mechanism, the compartment comprising first and second movable elements that are movably coupled to the hub and configured to engage the actuating surface and move relative to the hub based on rotation of the hub relative to the actuating surface.