poultry carcasses hanging by their legs from a moving overhead conveying line are presented to corresponding carcass processing fixtures moving in a closed loop of travel around an upright axis . as each carcass is presented to its fixture , a holder on the fixture takes control of the carcass and stabilizes it with the breast facing outwardly and the neck hanging downwardly against a sloped centering channel . once the carcass is stabilized , an arm carrying a slitting knife swings up toward the front throat area of the neck but before the knife can contact the neck skin , a stretcher device mounted in close proximity to the knife but operable in a stretching motion relative to the knife engages the skin and pulls it downwardly into a taut condition to facilitate penetration and severance by the knife . the stretcher is operated in its stretching motion by camming engagement with the underside of a shoulder yoke on the holder as the arm presents the knife to the carcass .