Why would a Canada goose abandon her egg?

geese cant tell if eggs are bad but the mother can comunicate with the babies while they are forming and i have seen it happen where every goose nest in the area there is always one bad rotten egg left over in the nest after hatching.

Usually the geese don't know they are bad until it is past the time they are supposed to hatch. So they probably wont abandon it until after hatching time.