The industry kills them right away because they're not selectively breeded to grow as fast as broilers do. Egg laying chicken have been selectively bred to lay high quantities of eggs instead
Due to modern selective breeding, laying hen strains differ from meat production strains (broilers).
As an aside, in both cases, the selective breeding has led to all kinds of health issues for these birds. Broilers can hardly walk due to being fast-growing. Egg laying chickens have all kind of bone health problems due to producing lots of eggs (takes a lot of calcium to produce an egg shell)