Egg embryo is adequately developed it hatches, i.e. breaks out of the egg's shell. Some embryos have a temporary egg tooth they use to crack, pip, or break the eggshell or covering. The largest recorded egg is from a whale shark, and was in size. Whale shark eggs typically hatch within the mother. At and up to , the ostrich egg is the largest egg of any living bird, though the extinct elephant bird and some dinosaurs laid larger eggs. The bee hummingbird produces the smallest known bird egg, which weighs half of a gram (around 0.02 oz). Some eggs laid
The Goose That Laid the Golden Eggs goose that lays the golden egg", sometimes shortened to "Killing the golden goose", derives from this fable. It is generally used of a short-sighted action that destroys the profitability of an asset. Caxton's version of the story has the goose's owner demand that it lay two eggs a day; when it replied that it could not, the owner killed it. The same lesson is taught by Ignacy Krasicki's different fable of "The Farmer:" There is another variant on the story, recorded by Syntipas (Perry Index 58) and appearing in Roger L'Estrange's 1692 telling as "A Woman and a Fat Hen"