A slaughtering installation for processing poultry is adapted to be used in combination with a conveying assembly for conveying poultry which is suspended from their legs in a transport direction. The slaughtering installation comprising a killing device with poultry positioning device for positioning the neck region of the poultry suspended from the conveying assembly, the killing device further comprising cutting device for cutting into the neck and thereby opening at least one blood vessel in the neck region of the poultry. The positioning device comprises a back neck guide along which the back side of the neck of the poultry is guided, and a breast neck guide along which the breast side of the neck of the poultry is guided.