High-production laying hens are pushed to the physiological limits of egg production, creating welfare challenges from laying fatigue, bone weakness, and the cumulative toll of year-round production.
Laying fatigue is a welfare consequence of extreme selective breeding for production. Hens whose ancestors produced eggs seasonally for reproduction are now producing daily year-round, a physiological demand that wears out their bodies rapidly. The hen that cannot stand because she has exhausted her calcium and energy reserves is experiencing a welfare failure built into the genetics of modern commercial laying breeds. Slower production rates, breed diversity, and earlier retirement ages would reduce but not eliminate this problem. Understanding laying fatigue helps owners of backyard or rescued ex-commercial hens provide appropriate supplementary calcium and nutritional support.