I have 3 RIR and 6 leghorns. Every so often I get a double yolk egg from each. I am wondering how to tell which one of the hens are laying the double yolk eggs. When I start hatching eggs I would like to get the eggs from the ones that do lay the double yolks. If it is passed on. I do not want to hatch a double yolk egg, afraid there may be toubles with the chick. Thank You!