Winner Geneva, 15

by Geneva
(Chile)

Life in a Shell

Hidden in a small, dirty-white shell lies a tiny dot that holds all the ingredients for life. Through an exciting twenty-one day journey, a chick in a fertilized egg will grow to a fully formed bird that could eventually have chicks of its own! Let's follow the embryo's three week voyage, and watch its progress from egg to chick!

During the first week, the chick grows from 0.0002 grams - a tiny dot - to 0.57 grams, more than two thousand and five hundred times as big! By the end of just the fourth day, all the embryo's organs have begun to develop, and most of its parts are identifiable. In fact, at the finish of the third day the beak, wings, and legs become distinguishable, and after a while the chick curls up in a C shape. Soon, the beginnings of digestive and respiratory systems are noticeable, as well as the internal organs, though the chick does not quite look like a bird yet!

But the embryo grows quickly, and at a mere ten days, the feathers are starting to grow and the beak hardens. Just a little later, it moves into hatching position with the beak near the egg shell, ready to peck its way out. The front of the upper beak hardens until it forms an "egg tooth", which will be useful for pecking through the shell but afterwards will fall off. By the end of the second week, the chick has grown to about a third of its final size and looks more and more like a bird!

Throughout the third week the chick gets bigger and bigger, until on the twentieth day, it will pierce the small air cell on the top of the egg and begin to breath. When the twenty-first day arrives, the chick finally begins to escape! It starts to peck at the egg shell with its egg tooth, though it has to change positions and rest several times. At last the chick is able to kick off the bottom of the shell! All the activity of breaking its way out of the shell has made the chick exhausted, and it rests, allowing its down to dry off. Eventually, the chick is able to walk around and the hatching process is complete!

From the 0.0002 gram speck inside the egg to a cute, fluffy chick, the embryo's voyage has finished, taking the chicken through three weeks of growing, all within the confines of an egg shell. From hen to egg and back again, the fascinating process of embryo development roles on!