Photo of a man (Dominic Wright, SLU) holding a white hen, both against a bright yellow background.

Mission: Reviving extinct species and improving the welfare of Swedish chickens

News published:  10/05/2026

Research is currently being conducted into the possibility of bringing extinct animal species back to life. How? Well, by first successfully reintroducing already domesticated animals into the wild. Could this be a way to correct human mistakes and help our planet? That remains to be seen.

For thousands of years, humans have domesticated various animal species, fundamentally changing their behaviour, appearance and genetic traits.

These domesticated animals have been shaped through generations of selective breeding, where humans have chosen which individuals are allowed to reproduce – in order to reinforce desired traits. Shaping animals according to human needs has brought both major advantages and disadvantages.

We have bred animals for what was needed at the time, for example in order to get more milk from cows or more eggs from chickens, says Dominic Wright, recently appointed professor at the Swedish University of Agricultural Sciences.

The benefits are clear: human needs have been met. However, for the animals this has sometimes come at a cost, such as more fragile bodies, reduced resistance to certain diseases, or lower tolerance to stress.

At the same time, there are cases where animals, for various reasons, have had the opportunity to return to their original wild state - what is called feralization. This has raised a number of intriguing questions.

The changes are surprisingly extensive – not only in traits affecting appearance, but also in health, behaviour, and even the size and composition of the brain, says Dominic Wright.

So is it then possible to reverse the negative aspects of domestication? And how is this connected to the possibility of reviving extinct species? 

Let’s take a closer look behind the scenes!

From wild → domesticated → feral

In the autumn of 1992, the most powerful hurricane ever to hit Hawaii – Hurricane Iniki – struck the islands. The eye of the storm passed directly over the island of Kauai, destroying 90% of its buildings, including countless chicken coops.

This marked the beginning of a feralization process that, on the other side of the Pacific, has turned domesticated chickens into wild survivors.

The process of feralization has been studied by researchers to understand whether domesticated animals can survive in the wild, and how they change when once again shaped by nature – returning to a life without human support or control.

What struck me when I first saw these feral chickens was how quickly they had reverted to behaving and looking like a wild species. In just 30 years, they have become a completely different kind of bird – now a feral one, says Dominic Wright.

The feral chickens on the island of Kauai have therefore become an ideal study system for understanding how the transition from domesticated to feral occurs, and what actually changes when animals themselves drive their own evolutionary development for survival.

The results from this research may pave the way both for recreating extinct species and for improving the lives of domesticated chickens in Sweden..

Back to the wild – how far can we go?

It goes without saying that animals living without human management must become tougher and more robust in order to survive in the wild – against diseases, predators and other threats, says Dominic Wright.

As an unintended consequence of many years of breeding chickens to meet the high demand for eggs, modern laying hens have in many cases become more fragile, both physically and mentally. At the same time, the world is facing a growing challenge: antibiotics, including antiparasitic treatments, are losing their effectiveness. For chickens that cannot resist parasitic infections on their own, such as many Swedish laying hens, this could in the near future have fatal consequences.

We are therefore studying which genes are passed on in order to ensure survival in the return to the wild. We are particularly interested in identifying the genes that allow feral chickens to survive parasite infections, since these animals are no longer dewormed or vaccinated but must cope on their own, says Dominic Wright, and continues:
In simple terms: what is it in the genes of the feral hen that makes her more resilient – and can we transfer those traits to today’s domesticated chickens?

Reviving extinct species

This brings us to the question of “reviving” extinct species. Is it possible? And if so, how?

In research, we combine mapping the DNA of extinct animals to understand how the species was structured, with attempts to shape the closest living species to resemble its extinct ancestor as much as possible, says Dominic Wright.

The species that Dominic Wright and his colleagues are currently working to revive is the passenger pigeon, which was driven to extinction by humans just over a hundred years ago.

They lived in enormous flocks – sometimes so large that the sky would darken when billions of birds flew overhead – and were often described as ‘ecosystem engineers’ that promoted biodiversity, he continues.

If researchers succeed in reviving the species, the positive environmental effects it once had could also return.

And that could be a first step towards reviving more extinct species in the future – while also improving the lives of the animals we already have, says Dominic Wright.

– Yes, this is exactly what we observe in the feralisation process of chickens in Hawaii: traits related to appearance, physiology and behaviour can “re-emerge” as animals return to the wild and again become more similar to their wild relatives.

– The short answer is: we don’t know – yet. In current efforts to recreate the passenger pigeon, we have access to much more genetic material, for example from preserved specimens. This increases the chances of success compared to species where DNA is only available from fossils or fragmentary remains. Time matters: the passenger pigeon has been extinct for only about 100 years, compared to around 4,000 years for the mammoth.

– By identifying genes that make feral chickens more resilient, we may eventually be able to introduce these traits into the breeding of domesticated chickens. This could lead to healthier animals that are better able to cope with both their environment and disease – something that may be crucial in a changing world.

Portrait of a man (Dominic Wright, SLU) standing indoors.
Dominic Wright, professor at the Swedish University of Agricultural Sciences (SLU). Photo: Lisa Chröisty, SLU

Fact Box

Dominic Wright is originally trained in animal genetics and, since 2026, is Professor of Molecular Animal Genetics. You can read more about him and his ongoing research below.

Profile page for Dominic Wright

Key concepts

Domestication = The process by which wild animals are adapted to life with humans through selective breeding over many generations.

Feralisation = When domesticated animals, over generations in the wild, return towards a wild state.

Resilience = The ability to withstand disease, stress and environmental changes.

De-extinction = Attempts to recreate extinct species using DNA and closely related living species.

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