Chan, Franks and Hayek, 2022
The authors calculated the land use and demographics of the chickens that would be required if the United States continued to consume 20 million metric tons of chicken meat annually, but switched to slower growing breeds with outdoor or pasture management.
The authors created estimates of current conventional flocks (Ross 308) and flocks of three slower growing chicken breeds. They derived estimates from data and guidelines published by the USDA National Agricultural Statistics Service (NASS), National Chicken Council, Global Animal Partnership (required outdoor access space for certification), Humane Farm Animal Care (required pasture space), Aviagen (data on slow-growing breeds).
If all conventional chickens were replaced with slower growing breeds, the chicken population is estimated to increase by 44.6%–86.8%, depending on the breed. Using CAFOs to raise the slower growing breeds would require 19.9%–30.6% more land. Occasional outdoor access only resulted in a minor increase in land compared to exclusive CAFO housing. However, 43.8%–60.1% more land would be required to house slower-growing breeds on pasture.
If the goal was to switch to slower growing breeds, but keep land use the same, it would require a significant reduction in meat consumption. For example, a 17.3% decrease to maintain intermediate growing breeds raised in CAFOs.
A strength of this study is the consideration of direct and indirect (land for feed) land use to raise chickens. A limitation acknowledged by the authors is that the estimates do not take into account factors such as the potential differences in mortality or slaughtered carcass rejection rates.
According to the authors, this study implies that significantly reducing chicken consumption could reduce the barriers to shifting to slower-growing breeds while mitigating the impact on wild habitats.