Check out this fascinating video of Great Blue Herons hatching in the wild:
Great Blue Herons Hatching

Below is some additional background information provided from the website www.allaboutbirds.org

About the Herons

This Great Blue Heron nest is in a large, dead white oak in the middle of Sapsucker Woods pond, right outside the Cornell Lab's Johnson Center for Birds and Biodiversity. Herons have nested here since summer 2009, hatching and fledging four young each year and raising them on a steady diet of fish and frogs. Though neither bird is banded, you can identify the male by the absence of a hallux (the rear-facing toe) on his right foot. Adult herons can be up to 4.5 feet tall, with a wingspan up to 6 feet. Despite their large size, they typically only weigh around 5 pounds.
Herons usually lay 2-6 eggs and share incubation duties for 25-30 days. Incubation begins with the first egg, and the young hatch asynchronously (not at the same time) over 2-5 days. After hatching, it'll take 7-8 weeks before they fly from the nest for the first time.

About the Nest

In 2009, the herons brought in the first few twigs that would become the first known Great Blue Heron nest in the history of Sapsucker Woods. Early in the spring of 2012 we installed two cameras to bring the hidden world of their nesting habits into full view. The nest itself is nearly four feet across and a foot deep, and wraps almost entirely around the trunk of the tree. The birds have slowly built up the nest over the last three years.