How gene editing creates both opportunities and risks for animal welfare
Genetic engineering — particularly CRISPR-Cas9 gene editing — offers unprecedented ability to modify animal genomes for human purposes. For animal welfare, this creates a profound dilemma: the same technology that could eliminate inherited diseases and reduce suffering could also be used to create animals better adapted to intensive production systems rather than improving those systems. How the technology is directed matters enormously.
In-ovo sexing technology — including some gene editing approaches — allows determination of egg sex before hatching, eliminating the killing of 7 billion male chicks annually in the layer hen industry. Several European countries have mandated this technology. Gene editing to produce female-only offspring is in development and would address this welfare issue at the genetic level.
Gene editing can make animals resistant to specific diseases — PRRS-resistant pigs, mastitis-resistant cattle, avian influenza-resistant chickens. This reduces animal suffering from disease and reduces antibiotic use. However, it may also enable more intensive production by removing a natural constraint on density without addressing the underlying welfare problems of intensive systems.
Controversial but actively researched: gene editing to reduce pain sensitivity in animals farmed in painful conditions. Chickens edited to have reduced sensitivity to the contact dermatitis caused by ammonia-soaked litter, for example. This raises profound ethical questions — is reducing an animal's capacity to suffer an improvement in welfare, or a justification for continued harmful practices?
Gene drives — genetic changes that spread through wild populations — could theoretically reduce diseases that cause widespread wild animal suffering. Research on using gene drives to eliminate myxomatosis in rabbits, rinderpest in wildlife, or parasites in fish is in very early stages. The ecological risks of population-level genetic changes are enormous.
Current fast-growing broiler chickens already suffer from cardiac, respiratory, and musculoskeletal problems from growth rates exceeding their bodies' capacity. Genetic enhancement of growth rates could intensify these welfare problems. The broiler genetic companies control most of global chicken genetics — their research priorities matter enormously.
Dairy cows already produce 10-15x more milk than they evolved for, causing metabolic diseases and reducing lifespans. Gene editing to enhance milk production further risks compounding existing welfare problems. Productivity enhancement without welfare safeguards is a predictable misuse of genetic technology.
Complex organisms are not just collections of independent genes — edits can have pleiotropic effects (one gene affecting multiple traits) and unexpected interactions. Animals created through gene editing may experience welfare problems that weren't anticipated during development. Long-term monitoring is essential.
Welfare advocates have proposed principles for evaluating genetic engineering from an animal welfare perspective:
Genetic engineering will increasingly shape the animals of the future — both farmed and wild. Whether this technology serves animal welfare or exploitation depends entirely on the governance frameworks, research priorities, and ethical standards we put in place. This is an active advocacy frontier with enormous stakes for billions of animals.