One pair swans have been sitting on a clutch of 5 eggs due to hatch next week but last night an egg disappeared. I've been hanging wolf urine vials and sprinkling dried wolf urine around the nest. No egg was found, there were no feathers and the nest appeared to be untouched. I did see some flies on one egg yesterday. Would the swans know to oust a rotten egg from the nest even though they can't smell?

Thank you, Betty