So what happened? In nearly four years, the geese have never gotten out, and the only way I can imagine she did was by going over the fence. But it's a four foot fence and I've never seen her achieve a lift of more than 2 feet. These are not flighty birds - they prefer to walk. Griselda is a good mother and has barely left her nest in a month. What caused her to leave her nest and go over the fence? The only thing I can think of is that she was going after a predator, a fox perhaps. But why wouldn't Teague, the gander, have been the one to do that? He's been standing guard since Griselda started sitting. Also, none of the other animals were bothered.
It's a mystery, and a shame.