Part No. 27 of the National Flock Performance Study compiled by Don Bell, poultry specialist emeritus at the University of California–Riverside, documents a steady improvement in performance parameters for the industry.

The National Flock Performance Study data denotes genetic progress and advances in disease prevention, nutrition and management from 1997 to 2009. Average U.S. hen performance shows a 6.6% improvement in contribution margin—the difference between egg revenue (a function of egg price, feed conversion and egg mass) and feed costs per hen housed (influenced by feed conversion efficiency, daily intake and cost of feed).


The study showed a 37.5% increase in post-peak persistence. Hens averaged 31 weeks over 90% in the 2009 survey compared with 19 weeks in 1997. This increase was attained despite a 2.5% decrease in average hen-day peak, which attained 97.7% in 1997 and 95.1% in 2009. Total egg mass increased by 6.6%, which was attributed to a combination of a 4.8% increase in hen-housed production through 60 weeks and a 2.6% improvement in livability. Feed conversion improved by 1.1% from 1.84 (pounds of feed per pound of egg) in 1997 compared with 1.82 in 2009. Feed cost expressed in cents per dozen was almost static, demonstrating that the escalation in feed cost was offset by improvements in production efficiency.

Within the limitation of the sample size, the data shows a steady improvement. In 1997, 203 flocks with an average of 66,000 hens amounting to 13.4 million birds comprised the sample. In 2009, this number was reduced to 165 flocks averaging 48,000 hens for 7.9 million in total.