Bob Fischer

“When we say that cage-free egg production costs only 10% to 20% more to produce at the level of retail (not farm) prices, we are assuming that the same distribution system is used for cage and cage-free eggs. When both cage-free and cage eggs are sold, it likely costs more to distribute cage-free eggs. The cage-free sector is small, prohibiting them from realizing the economies of scale enjoyed by the cage egg sector.
Also, they are often different types of eggs. Studies have shown that about half of this 57% pre- mium charged for cage-free eggs is due to the fact that cage-free eggs tend to be brown eggs instead of white eggs. Consumers value brown eggs more, and stores have learned that when they bundle brown eggs with a cage-free production system they can charge particularly high prices. Moreover, cage-free eggs are often targeted to more affluent consumers and come in more elaborate packaging. In economics, this is referred to as price discrimination, and grocery stores probably charge a higher premium for cage-free eggs partly because they can.”
― Bob Fischer, The Routledge Handbook of Animal Ethics