The US egg industry underwent massive consolidation from the 1940s-1990s, with the average flock size increasing from 10,000 birds to over 500,000. Today, there are around 60 large companies with over 1 million layers each, accounting for 95% of US egg production. Most egg-laying hens are now confined in battery cages at high densities, though alternatives like cage-free and free-range systems are growing. Automation is also widespread in egg production facilities for functions like temperature control, feeding, and egg collection. Converting to alternative housing systems would cost the industry an estimated $7.5 billion.