Colossal Biosciences, a company dedicated to bringing back extinct species, has managed to hatch 26 healthy chickens from an artificial egg, the company announced Tuesday.
National Geographic published an article on Colossal’s achievement using its silicone-membrane synthetic shell system that was cited by the company. With this success, Colossal is now closer to bringing back extinct bird species like the dodo.
Audacy podcast Something Offbeat has covered Dallas-based Colossal’s efforts to bring back extinct species like the woolly mammoth.
Already, the company has genetically engineered gray wolves to carry the key traits of their extinct relative, the dire wolf, which disappeared from the planet around 10,000 years ago. Dire wolves were featured in the HBO show “Game of Thrones” and star Kit Harington even serves on the board of Colossal.
According to the company, the artificial egg system includes two components – a semi-permeable silicone-based membrane housed inside a rigid hexagonal support cup. MIT said the plastic cups were 3D-printed.
“The membrane is engineered to replicate the gas-exchange function of a natural eggshell — allowing oxygen to pass through while retaining moisture and blocking contaminants,” Colossal explained. Andrew Pask, chief biology officer for Colossal, said it allows for comparable exchange as biological shells.
There is also a clear window where scientists can peer in and observe embryo development. Colossal said the design is scalable, meaning it can accommodate small, humming-bird sized eggs as well as the soccer ball-sized of the extinct South Island giant moa. Scientists said this window could benefit evolutionary biologists going forward.
“To see them all moving around in their artificial eggs was absolutely mind blowing,” said Pask, according to an article from MIT. “You really feel you can grow life outside of the womb.”
What makes this model different from other shell-free hatching attempts is the “passive diffusion” of oxygen through the silicone. To test the system, scientists examined eggs laid by real hens within 24 to 48 hours of laying, selected candidates and transferred the egg’s contents into the artificial structure.
“All upstream biology, from fertilization through laying, still occurs in a living bird,” said Colossal.
When it comes to bringing back extinct species like the dodo or giant moa, Colossal’s scientists would need to introduce species-specific genetic edits before they bring the artificial egg into the mix. They have plans for that too, involving primordial germ cells, or stem cell precursors to sperm and egg cells.
Colossal hasn’t yet released its hatch rate for the 26 chickens and independent scientists have not yet been able to evaluate the underlying methodology. Its artificial egg may help conservation efforts, but Stuart Pimm, a Duke University ecologist, added that for most threatened bird populations, the more immediate leverage remains in reducing habitat loss, building collisions, and predation by outdoor cats are more pressing issues for birds.
MIT stressed that “Colossal isn’t close to re-creating the moa,” with the artificial egg. It explained that, “before that could happen, scientists would need to study DNA data from old moa bones and insert thousands of genetic changes into the genome of an existing bird.”
Additionally, MIT noted that “some scientists also think Colossal is taking too much credit for its artificial eggshell,” announced in a YouTube video that includes a joke about whether the chicken or the egg came first. Previously, scientists also criticized its dire wolf announcement for exaggerating.
“This time, Colossal’s fluffed-up assertion of having created the ‘first-ever shell-less incubation system’ is what’s raising hackles among the small flock of scientists who’ve been working on the technology for years.” For example, Katsuya Obara at the University of Tsukuba in Japan, who in 2024 hatched chickens from beneath transparent plastic film said its basically a modification of existing methods.
Beyond the artificial egg, Colossal is also working on an artificial womb for its goal of bringing back the woolly mammoth.
“We’re looking at every single facet of what’s happening during a mammalian pregnancy to unpack exactly how we then go about recapitulating that,” Pask said.
