Pre-hatch Baby Dinosaur Fossil Found - Lufengosaurus -

A fossil of a pre-hatch baby dinosaur has been discovered in Early Jurassic strata (197-190 million years ago) in Yunnan Province, China.
The discovery was announced on April 11 by a research team from the University of Toronto and other institutions.
Based on the shape of the bones, the fossil is presumed to be that of the sauropodomorph Lufengosaurus.

A detailed examination of the bones revealed that the femur—the muscle part of the hind leg—was well-developed, suggesting that "Lufengosaurus may have moved its muscles even inside the egg to prepare for hatching."
It was also found that the growth of Lufengosaurus inside the egg was fast compared to modern animals.

In 2006, an egg fossil of the sauropodomorph Massospondylus, just before hatching, was found in Early Jurassic strata (190 million years ago) in South Africa.