I just read how serious your goose's problem is. Can you bring her inside a house or building? if you can, I thnk you should. I have no ideas for how to keep her calm while you clean the area..... don't use any of the "caine" topical painkillers. I thnk they are toxic to chickens, so they might be toxic to waterfowl too. Do you have betadine? Use that when you clean the wound. You might want to let the goose swim in saltwater while the wound is healing - just don't let her drink it. keep us updated.