A spreader disk assembly for spreading crop residue such as straw discharged from an agricultural harvesting machine, and more particularly, which has a bat support mechanism that enables the bats to be quickly and easily hingedly or pivotally convertible from a deployed spreading mode to a flattened stowed mode for windrowing, which does not require removal of the bats, or the disk from the spreader. A locking mechanism is provided that enables the quick and easy conversion and securely holds the bats in both modes.