Increased production and being fertilised are not the same. Fertilised eggs are obvious (to me) and I don't eat them. Never seen fertilised eggs in store bought packets, I assume if they do have roosters as you say they also have a machine do a candling on them before being sent out. Also 90% of eggs i eat these days come from hens (currently) without a rooster (I have personally seen them) so they are 100% periods and I don't need to candle them.