I got some brilliant stuff from France: it's rosin/resin but can't remember the make. Rub the powdered stuff into the feathers, plunge in really hot water for about a minute, then into cold to set it and pretty much pull the feathers out in handfuls. It worked better on ducks than the geese, but I think I was a bit abstemious on the breast down and will be more generous next time.
Made an easy job of it, where as before, I'd have prefered to keep my geese for eggs.