not sure if this will help, I found it on poultryhelp.com -
No-yolkers are called "dwarf", "wind" [or, more commonly, "fart"] eggs. Such an egg is most often a pullet's first effort, produced before her laying mechanism is fully geared up. In a mature hen, a wind egg is unlikely, but can occur if a bit of reproductive tissue breaks away, stimulating the egg producing glands to treat it like a yolk and wrap it in albumen, membranes and a shell as it travels through the egg tube. You can tell this has occurred if, instead of a yolk, the egg contains a small particle of grayish tissue. In the old days, no yolkers were called "cock" eggs. Since they contained no yolk and therefore can't hatch, our forebears believed they were laid by roosters. This type of egg occurs in many varieties of fowl. We've found them in chickens, both standard and bantams, guineas and Coturnix Quail (about the size of a small marble). We'll get photos of any more we get in the future.