THE BASIC PRINCIPLES OF FERTILE SWAN EGGS

I am no specialist on swans. I rather feel that a night-time predator filched the eggs. I have read folks mention that their birds( chickens, geese, what ever) clear away infertile or nonviable eggs from their nest. In forty decades I haven't had a chicken take out their own egg/s within the nest besides unintentionally. Our advanced incubation in