Wait, you thought they were eggs? Hahaha! Oh my friend, it happens to the best of us, including yours truly.
You see, Hank, Brank's father, was a potato who for many years believed himself to be an egg until his uncle revealed the truth on his deathbed. He fell in love with and married Brenda, an egg, and later had two chicken nugget children Brank and Handa.
As for the egg vendor, who knows! He could be an egg, a potato, or a wheel of cheese!