From Egg To Chick:

Introduction

THE BIRD EGG IS A MARVEL OF NATURE. WHAT IS more fascinating than to see a fully-developed baby chick emerge from an egg? Just three weeks of incubation transforms a seemingly lifeless chicken egg into an active, living being.

If you are interested in a science project for school or 4-H, none can be more interesting and informative than the study of the chicken egg and its development from the unincubated stage to the emergence of the chick from the shell. The developing chick in an egg is called an embryo, and a careful study of the different stages of embryonic development will uncover many interesting facts.

This circular has been designed to help you study incubation and embryonic development. Plans are included for two small, inexpensive incubators which you can make at home or school. Many small commercially built incubators can be purchased at reasonable prices.

Incubation of eggs will show you the effects of heat, air, and moisture control on hatchability. But don't stop your study with the incubation of eggs. Many other interesting aspects of the egg and the chick may be selected for study. For example you may want to find out how an egg is formed, what its different parts and their functions are, and how a chick embryo develops. And there are many other interesting topics you can investigate.

Eggs have been incubated by artificial means for thousands of years. Both the Chinese and the Egyptians are credited with originating artificial incubation procedures. The Chinese developed a method in which they burned charcoal to supply the heat. They also used the hot-bed method in which decomposing manure furnished the heat. The Egyptians constructed large brick incubators which they heated with fires right in the rooms where the eggs were incubated.

Over the years incubators have been refined and developed to the point where they are almost completely automatic. The greatest development has occurred in this century. Modern commercial incubators are heated by electricity, have automatic eggturning devices, and are equipped with automatic controls to maintain the proper levels of heat, humidity, and air exchange. Present-day commercial incubators vary in capacity from a few thousand to many thousands of eggs, and they have made possible the development of modern hatcheries which produce almost 100 percent of all the chickens grown in this country.

Both still-air and forced-draft incubators are used in hatcheries. However, all the new ones are forced-draft; that is, they have fans to circulate the air. They are capable of maintaining more even temperature, humidity, and oxygen levels than still-air incubators. Many modern commercial hatcheries also use separate setter and hatcher machines.

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