HENS that are unable to produce their own chicks have successfully acted as surrogates for rare chicken breeds, Scots scientists have revealed.

And the advance – led by the University of Edinburgh’s Roslin Institute – could help boost the breeding of endangered birds and improve production of commercial hens.

Using gene-editing techniques, scientists injected specialised stem cells – called primordial germ cells – from another breed of chicken into the eggs from the surrogate chickens. They found that the adult hens then produced eggs which contained all the genetic information from the other chicken breed.

The Roslin team used a genetic tool they had previously developed called TALEN to delete a section of chicken DNA.

They targeted part of a gene called DDX4, which is crucial for bird fertility. Hens with the genetic modification were unable to produce eggs but were otherwise healthy.

DDX4 plays an essential role in the generation of primordial germ cells, which gives rise to eggs.

The surrogate chickens were the first gene-edited birds to be produced in Europe. Experts said the cells could potentially be used to help breed birds of other closely related species, as long as a supply of primordial germ cells is available from a donor bird.

The study involved scientists from poultry genetics company Cobb-Vantress, and is published in the journal Proceedings of the National Academy of Sciences, USA, and was funded by the Biotechnology and Biological Sciences Research Council, Innovate UK, Horizon 2020 and Cobb-Vantress.

Lead researcher Dr Mike McGrew (pictured), from the Roslin Institute, commented: “New ideas are needed if we are to save many of our bird species. These chickens are a first step in saving and protecting rare poultry breeds from loss and preserving future biodiversity of our poultry from environmental and climate changes.”