SWANS EGGS INCUBATION TIME NO FURTHER A MYSTERY

I am no skilled on swans. I somewhat feel that an evening-time predator filched the eggs. I've listened to persons claim that their birds( chickens, geese, whichever) take out infertile or nonviable eggs from their nest. In 40 yrs I have never had a hen eliminate their own personal egg/s with the nest in addition to accidentally. The strength of t