Sounds like we had the opposite effect on eggs. I had one white rooster hatch from one shipment of ten eggs. Out of 4 sets of White Cornish eggs I managed to get 13 eggs to hatch. Pretty dismal, 4 hens and 9 roosters. One hen was always smaller and died about a month ago. She was the only hen that hatched from one seller. Too bad you’re not closer I have a couple white roosters I won’t be using. 
Of my Dark Cornish the roosters died leaving me 5 very nice hens. They would be the ones laying now as the Whites are younger. So probably hatching the mixed ones this time if fertile . Getting a few from the Whites but are pretty small right now.