On the B744 Freighter we often carried Grooms when carrying horses.
Grooms had to be have a proper safety briefing which included the operation of the slide at the U/D door.
Additionally grooms had to be properly briefed on the use of the 'walk-about' oxygen unit as they were permitted to be down below with the horses during the flight.
Grooms were shown on a pax. manifest and had pax. tickets. but they knew exactly where the food was and were catered for!