This theory has been disproved in several magazine articles I have read.
I've also tried it to no avail. I have some hens who always lay a round egg and have produced both sexes.
Some more information would help. How many eggs are you talking about hatching roosters? That would make a difference, whether it is three out of three (perhaps not unusual) or 15 out of fifteen which would be. How many eggs total, that is how many in each batch are not hatching?
I once...