Asked by: Johnathan Holmes, Bristol
Only one bird has ever actually laid an egg in space. A quail aboard the Russian Soyuz TM-10 spacecraft laid an egg while travelling to the Mir space station in 1990. It seems likely that other birds would be able to physically lay eggs in zero-g, but successfully incubating those eggs is much harder. Experiments with both quail and chicken eggs in space show much higher rates of birth defects in the bird embryos.