The invention relates to a method and a device for processing a carcass part of slaughtered poultry, which carcass part comprises at least part of a rib cage, meat which is naturally present on said rib cage, a neck opening, and a wing joint, the carcass part having an interior which method comprises the following steps: applying and fixing the carcass part to a product carrier, which product carrier is moveable and which product carrier engages the interior of the carcass part, moving a wing-joint positioning member via said neck opening into the interior of the carcass part, the wing-joint positioning member being provided with one or more wing-joint positioning surfaces, which are arranged in such a manner that, in a defined position of the first wishbone blade with respect to the carcass part, the wing-joint positioning surfaces hold said wing joint into a predetermined position, exerting an internal pressure on the carcass part, in such a manner that said one wing joint is supported in the predetermined position by a wing-joint positioning surface of the first wishbone blade.