That may be true, or it may be just a coincidence. This year I've let my broody hens hatch out chicks each time they want to set, and there are less pullets in the For Sale pen than cockerels in the For Dinner pen. And there seems to be more than the usual number of rabbits in my yard, both cottontails and swamp rabbits. But that could be due to my neglected veg garden that I never fully harvested.
I don't think there could me more than a single grain of truth in the pointy/roo round/hen egg theory. It sure would be handy if it were true, all those hatcheries could fire their high-salaried vent sexers and replace them with anyone who could tell the difference in egg shapes.