On May 19, Dallas-based Colossal Biosciences, which last year made headlines when it effectively de-extincted the dire wolf, announced that it had hatched a flock of 26 live chicks from fully artificial eggs. The technology behind the breakthrough can be later applied to bring back the dodo and New Zealand’s giant, flightless moa—both on Colossal’s de-extinction ‘to do’ list…

…Designing an artificial shell is not easy because a natural shell is deceptively complex. Made principally of calcium carbonate arranged in a crystalline structure, a typical egg shell is no more than 0.4 mm thick, and covered with up to 17,000 tiny pores to allow for gas exchange with the ambient atmosphere—carbon dioxide out, and oxygen in. There are, too, a pair of slick inner membranes in the egg that perform another critical function, protecting the growing chick from invading bacteria. But those membranes have to be exceedingly thin…

…The egg Colossal invented was very different. The inner membranes were made of vanishingly thin silicon using a proprietary technology that Colossal is planning to patent. The shell itself was only about two-thirds of a shell—a titanium structure that resembles nothing so much as a soft-boiled-egg cup with its top missing, albeit with hundreds of hexagonal pores to allow for gas exchange. Once a few dozen of the titanium eggs were manufactured, Colossal gathered fertilized chicken eggs from an avian farm the company owns and operates and transported them to the lab. There, the scientists gently opened the top of the egg and transferred the yolk and the white and the tiny embryo onto the titanium egg cup and covered the cup with a transparent lid. The embryos were about three days past fertilization when they were transferred, meaning that they had 18 days remaining in their three-week incubation cycle.

‘We place the egg into an incubator that controls the environment,’ says Lambert. ‘We then collect visual images at periodic milestones to understand how development is progressing.’ When the incubation period was done, the chicks began ‘pipping,’ using their beaks to break through the membrane just the way an ordinary chick breaks through its shell. Eventually, the 26 chicks were moved to the same Texas farm from which their eggs were collected, where they can live out their five to 10 year lifespan.

The breakthrough could help bring giant birds back from extinction.