By SCOTT McFETRIDGE
DES MOINES, Iowa (AP) — The nation’s egg producers are in the midst of a multibillion-dollar shift to cage-free eggs that is dramatically changing the lives of millions of hens in response to new laws and demands from restaurant chains. In a decade, the percentage of hens in cage-free housing has soared from 4% in 2010 to 28% in 2020, and that figure is expected to more than double to about 70% in the next four years. The change marks one of the animal welfare movement’s biggest successes after years of battles with the food industry. The transition has cost billions of dollars for producers who initially resisted calls for more humane treatment of chickens but have since fully embraced the new reality.