I have chickens, too, and I have only seen a yolkless egg when the girls are young, and those eggs are usually very tiny--maybe an inch long.
Eggs that haven't been candled or sorted (straight out of the bird) have all kinds of odd shapes, wrinkles in the shell, bits of shell stuck on the outside of the egg, no shell, round eggs or very long pointy eggs. The size varies a lot, too--sometimes an egg will be twice as big as normal, and have 2 yolks.
The yolk is formed first, then 2 layers of white, then the shell. Something happened in this case to cause the whites to form without the yolk--the folks in the egg production facility where I used to work said that a bad thunderstorm would cause a lot of double yolks.
I just haven't been the same
since that house fell on my sister.