Cracking eggshell Nanostructure 1 (IMAGE) McGill University Caption Over their short lifetimes though, bird eggshells change their strength. For example, they get thinner and weaker before hatching begins. Now, researchers investigating eggshell structure have zeroed in on the fine structure and mechanical properties of chicken eggshells, and shell changes associated with chick hatching. Credit "Carla Schaffer/ AAAS". Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.