'simmer chicken until it is soft'
The "Isekai Shokudou" (Restaurant to Another World) often has patrons commenting that the meat seems to have come from an animal raised for food alone. That is, beef from a cow that hadn't lived a life pulling a plow first, etc. Similarly, a chicken might have lived a life of laying eggs before finally being slaughtered, by which time it will have developed a tough and gamey meat that would require a lot of cooking.
A modern broiler/fryer is raised for only seven weeks or so before slaughter, and so has soft meat with a delicate flavor. The customers are assuming that the meat had been simmered for a long time to make it tender.