Wednesday, 18 June 2014

The Ins and Outs of Emu Egg Hatching - Part 1

Source: Backyard Chickens, Corny Caleb NJ Mar 26 2014

Most emu farmers would agree that incubating eggs is both a science and an art form. It is much more than just leaving it up to the incubator if you are interested in maximizing your hatch rate. We need to start with a strong foundation of "eggology" (not my term but I like it) and then we can tweak our reactions (this is the art) to problems as they arise. More on the scholarship but first some craftsmanship.

Nguna nynda ?, carved emu egg 2003,
 Barry Bellotti

Barry Bellotti's carved emu egg won the 20th Telstra National Aboriginal & Torres Strait Islander Art Award in 2003. According to Australia's Museums and Art Galleries of the Northern Territory website, Bellotti is a self-taught artist from Carnarvon, WA. Wow, the detail is amazing. The artistic message communicated to this emu farmer is one of caution: "these little beings will be in your respectful."

Source: The Digital Morphology Library
And on the flip side or the inside as it were another form of artistry is captured in the 2D and 3D visualizations of the internal structure of vertebrates as performed by Digital Morphology, part of the National Science Foundation Digital Libraries Initiative. Here we can see how the fully developed emu chick is positioned. At hatch it will pip in a downward motion through the internal membrane to reach the air supply. A second pip of the outer shell will expose the beak and one foot. With a push, the second foot and spine will fracture the shell and release the chick fully breathing and able to stand in only a few hours.

So let's start with an overview of the anatomy of an egg:

Egg Anatomy. Source

An egg consists of 4 primary components:
 a yolk which provides the food supply to the embryo

the albumen is the source of water supply and also a shock-absorber

the shell membranes protect the egg from external bacteria and help prevent rapid evaporation of egg moisture

the egg shell has thousands of pores which allow for gas exchange

The diagram shows a generic avian egg and we should ask the question as to whether generic avian eggs and their development would be the same for emus. According to the Laboratory for Early Embryogenesis, RIKEN Center for Developmental Biology, Kobe, Japan "emu and chick embryogenesis proceeds through similar stages, but developmental heterochrony between these two species is widely observed." In other words the developmental stages are the same but the timing of size and shape will differ.

Having said that, this video depiction of the development of a chicken embryo will help with our science of emu egg hatching. 

So stay tuned for the next blog when we will talk about managing the necessary egg weight loss as the embryo develops during incubation.