Chicks hatch from their eggs with the ability to walk and swim. After only 3 days in the egg, chicks begin to move. Researchers wanted to know if the movements in the egg prepared chicks for their big debut. They synchronized electromyograms for leg muscles, force, and video from late-stage embryos on days 15, 18 and 20 of their incubation. What they discovered was that the repetitive movements of the embryonic chicks were related to locomotion. These findings support the idea that chicks do in fact practice moving while still in the egg!
Click here to watch a fun video of a chick hatching.
Ryu YU, Bradley NS (2009) Precocious Locomotor Behavior Begins in the Egg: Development of Leg Muscle Patterns for Stepping in the Chick. PLoS ONE 4(7): e6111. doi:10.1371/journal.pone.0006111