I do not understand the mathematics behind the dilemma. I'm assuming only the firts chicks cost money, because down the line they will breed.
But feeding them, housing them - vitamins and doctoring costs a lot of money.
So anyone with couple or more chickens - how much does it cost to have them on the table? And realistically how many eggs do you get?
All of the comments about loss leader and factory scale vs. hobby farming are huge factors. Another is the predatory nature of poultry farming in the US. I don't know about Costco, but the other major producers, like Tyson and Perdue, have an extremely abusive relationship with contract farmers.