The third egg never hatched, but the fourth one hatched right on schedule. That makes for a four day gap in age between the two chicks, and there is a very noticeable size difference.
Because the mother only has two chicks to raise, I will not hand feed either of them. So they are destined to become breeding stock, not pets. Fortunately, they carry genetic mutations that are desirable for breeding, so it is just as well.