The Evolution of Hens

After only six generations of artily imposed group selection, breeding from the hens and the best groups out on the best individual hens, average days of survival increased from 160 to 348. Average egg mass per bird increased from 5.3 to 13.3 kilograms. At 58 weeks of age, the selected line had 20% mortality compared to the control group at 54%. A commercial line of hens, a large row with their clips unbeaked, had 89% mortality at 58 weeks. But yeah, 89% mortality is fucking insane. You're killing nine tenths of your fellow birds, man.