Chan Iris, Franks Becca, Hayek Matthew N
Department of Environmental Studies, New York University, New York, NY 10012, USA.
R Soc Open Sci. 2022 Jun 1;9(6):210478. doi: 10.1098/rsos.210478. eCollection 2022 Jun.
In 2018, over nine billion chickens were slaughtered in the United States. As the demand for chickens increases, so too have concerns regarding the welfare of the chickens in these systems and the damage such practices cause to the surrounding ecosystems. To address welfare concerns, there is large-scale interest in raising chickens on pasture and switching to slower-growing, higher-welfare breeds as soon as 2024. We created a box model of US chicken demographics to characterize aggregate broiler chicken welfare and land-use consequences at the country scale for US shifts to slower-growing chickens, housing with outdoor access, and pasture management. The US produces roughly 20 million metric tons of chicken meat annually. Maintaining this level of consumption entirely with a slower-growing breed would require a 44.6%-86.8% larger population of chickens and a 19.2%-27.2% higher annual slaughter rate, relative to the current demographics of primarily 'Ross 308' chickens that are slaughtered at a rate of 9.25 billion per year. Generating this quantity of slower-growing breeds in conventional concentrated animal feeding operations (CAFO) would require 90 582-98 687 km, an increase of 19.9-30.6% over the 75 577 km of land used for current production of Ross 308. Housing slower-growing breeds on pasture, the more individually welfare-friendly option, would require 108 642-121 019 km, a 43.8-60.1% increase over current land use. Allowing slower-growing breeds occasional outdoor access is an intermediate approach that would require 90 691-98 811 km, an increase of 20-30.7% of the current land use, a very minor increase of land relative to managing slower-growing breeds in CAFOs. In sum, without a drastic reduction in consumption, switching to alternative breeds will lead to a substantial increase in the number of individuals killed each year, an untenable increase in land use, and a possible decrease in aggregate chicken welfare at the country-level scale. Pasture-based management requires substantial additional land use. These results demonstrate constraints and trade-offs in animal welfare, environmental conservation and food animal consumption, while highlighting opportunities for policies to mitigate impacts in an integrated manner using a One Health approach.
2018年，美国有超过90亿只鸡被屠宰。随着对鸡肉需求的增加，人们也越来越关注这些养殖体系中鸡的福利，以及这些养殖方式对周围生态系统造成的破坏。为了解决福利问题，人们对在牧场上养鸡并尽快在2024年转向生长较慢、福利更高的品种有着广泛的兴趣。我们创建了一个美国鸡类人口统计学的箱式模型，以描述美国转向生长较慢的鸡、有户外活动空间的鸡舍以及牧场管理方式时，在国家层面肉鸡总体福利和土地利用的后果。美国每年生产约2000万吨鸡肉。相对于目前主要以每年92.5亿只的屠宰率屠宰的“罗斯308”鸡的人口统计学情况，完全用生长较慢的品种维持这一消费水平将需要鸡的数量增加44.6% - 86.8%，年屠宰率提高19.2% - 27.2%。在传统的集中式动物饲养场（CAFO）中养殖这种数量的生长较慢的品种将需要90582 - 98687平方千米的土地，比目前用于罗斯308生产的75577平方千米土地增加19.9% - 30.6%。在牧场上养殖生长较慢的品种，这是对个体福利更友好的选择，将需要108642 - 121019平方千米的土地，比目前的土地使用量增加43.8% - 60.1%。允许生长较慢的品种偶尔有户外活动空间是一种中间方式，将需要90691 - 98811平方千米的土地，比目前的土地使用量增加20% - 30.7%，相对于在CAFO中管理生长较慢的品种，土地增加量非常小。总之，如果不大幅减少消费，转向替代品种将导致每年屠宰的鸡的数量大幅增加，土地使用量不可持续地增加，并且在国家层面上肉鸡总体福利可能会下降。基于牧场的管理需要大量额外的土地使用。这些结果表明了在动物福利、环境保护和食用动物消费方面的限制和权衡，同时突出了利用“同一健康”方法以综合方式减轻影响的政策机会。
