You’ve probably heard the saying “which came first, the chicken or the egg?”. Well, we’ll probably never know what the answer is, but we can learn as much as we can about the Chicken and the Egg. In our case, we’ll discuss about chicken eggs. I am here to answer all the questions you might be having in relation to this topic.
So, sit back and get ready to learn all you need to know about chicken eggs.
The Anatomy of a Chicken Egg
Most folks generalize the parts of an egg into three parts only; the shell, the albumen and the yolk. However, you’ll be surprised to know that these are not the only parts. There are many components that make the chicken egg what it is. Here is the complete anatomy of a chicken egg.
You’ve probably heard the saying “which came first, the chicken or the egg?”. Well, we’ll probably never know what the answer is but we can learn as much as we can about the Chicken and the Egg. In our case, we’ll discuss about chicken eggs. I am here to answer all the questions you might be having in relation to this topic.
Anatomy of the Chicken Egg
Most folks generalize the parts of an egg into three parts only; the shell, the albumen and the yolk. However, you’ll be surprised to know that these are not the only parts. There are many components that make the chicken egg what it is. Here is the complete anatomy of a chicken egg.
1. The bloom or cuticle
The cuticle or bloom is actually a thin outermost coating of the shell which keeps out dust and bacteria. It does this by sealing the pores on the shell. By doing this, the cuticle also reduces moisture loss from the interior of the egg.
2. The eggshell
The eggshell is the hard outer part of an egg. It is what contains the outer color of an egg as we see it. It is composed of calcium carbonate crystals and has a grainy texture.
The shell is covered by around 17,000 tiny pores which makes it semipermeable. The semipermeability allows air and moisture to pass through the shell.
3. The outer and inner shell membranes
These two membranes are found immediately after the shell in the inner side of the egg. Both are partly made of keratin. Their main purpose is to protect the egg from bacterial invasion.
4. The air cell
When an egg is laid, it is usually warm. Once it cools, the outer and inner shell membrane separate forming the air cell. The air cell is usually formed at the egg’s larger end, This air cell is what you normally see as a crater at the end of a boiled egg.The size of the air cell increases as the egg ages.
5. The chalaza
The chalaza or chalazae are opaque spiral ropes of egg white. They are what hold the yolk in place at the center of the egg. Fresh eggs have more prominent chalazae.
6. The albumen
The word albumen is derived from the Latin word albus which means white. Generally, the albumen is mainly composed of water and contains around 40 different types of proteins. The albumen has two layers; the exterior albumen and the interior albumen. The outer or exterior albumen is a narrow fluid layer that is found next to the shell membrane and is usually very thin.
The interior or inner albumen is rather thick and is found next to the egg yolk. It contains a large amount of riboflavin. High quality eggs usually have inner albumen spread out much less and it usually stands at a higher position. In low-quality eggs, the interior albumen appears to be thin white.
7. The vitelline membrane
This is a clear casing that encloses the egg yolk. It is found between the yolk and the interior albumen.
8. The nucleus of pander
This is a plug of whitish yolk which really has no known special purpose.
9. The germinal disk
The germinal disk is a small white spot which is circular in space. It is actually 2 to 3 mm big and is located on the surface of the yolk. This is where the sperm enters the egg. The embryo begins its growth in the germinal disk then gradually sends the blood vessels to the yolk so as to get nutrients for growth.
10. The yolk
The yolk is the innermost part of the egg. Its color ranges from light yellow to a deep orange depending on the breed of chicken or the feed given to them. It contains more proteins than the albumen and also vitamins, minerals and some fat. Some of these include calcium, phosphorus, thiamine, riboflavin, Vitamin A, Iron and vitamin D.
How the Egg is Made
The egg goes through a series of stages before it becomes complete. The process begins at the point where an oocyte is produced from the hen’s ovary. This is what becomes the yolk. The yolk is then released into the oviduct where it can be fertilized if a sperm is available.
Whether the yolk is fertilized or not, it proceeds with its journey down the oviduct and is covered with the vitelline membrane, structural fibres and layers of albumin.
The movement of the egg causes the structural fibres to twist and form chalazae which hold the yolk in place. The eggshell is then deposited around the egg just before the egg is laid. From formation to movement It can take up to 26 hours for the Hen to lay an egg.
Chicken Egg Colors
Chicken eggs come in a wide range of colors. These include white, blue, cream and even green. It is possible to have a whole rainbow of egg colors.
So, what causes this color change. Eggs pick up their color from deposits of pigments as they move through the hen’s oviduct. The color can be attributed to the chicken’s genetics.
Different breeds of chicken produce eggs with different colors. These colors have been achieved mainly by cross-breeding. Despite the difference in color, the chicken eggs do not exhibit any difference in nutritional value.
This means that white shelled eggs are not necessarily less nutritious than brown-shelled eggs. The taste is also not different since the taste of the eggs is attributed to the food they eat. Let us have a look at some of the different breeds of chicken and the color of the eggs they produce.
1. White eggs
It is a common belief that white eggs are less nutritious than brown ones. This is false. In many cases, chickens with a white ear lobe tend to lay white eggs. Chicken breeds which produce white eggs include Bantams, Leghorns, Ancona, Buttercup, Campine, Hamburg, Holland, Houdan, La Fleche, Minorca, Modern Games, Polish, Sultan, Sebright, Sumatra and Icelandic.
2. Brown eggs
Brown eggs are said to be laid by chickens which have a red ear lobe. This is not always true but it happens in most cases. Brown eggs differ in shades, ranging from dark brown to light brown. Below is a list of brown eggs and the breed of chicken that produce them.
– Light brown: Shamo, Turken, Cochin.
– Moderately brown: Red stars, Black stars, Brahma, Buckeye, Dominique, Delaware, Golden Comet, Wyandotte, Rhode island, Orpington.
– Dark brown: Penedesenca, Malay, Langshan.
– Brown with white specks: Russian Orloff.
3. Cream or tinted
Chicken eggs can also be cream or have a tinted color. Breeds that produce such eggs include: Catalanas, Cubalaya, Faverolle. Hampshire Red, Phoenix and Rosecomb.
4. Other colors.
Eggs also come in other colors such as blue, green, olive and pink. The main breed of chickens known for producing blue eggs is the Araucana. The Araucanas can also produce green eggs. The Ameraucana lays blue eggs.
It is also possible for a particular breed of chicken to produce two different colors of eggs. Therefore, you should not be surprised when your two hens of the same breed produce eggs of different color from each other.
Comparison between free range and mass produced chicken eggs.
Eggs can be classified according to the way the chicken that lay them are raised. How chickens are kept and raised has been proven to have an effect on the nutritional value of the eggs. There are two main groups that come with method of classification, that is, free-range eggs and mass produced eggs.
Mass produced chicken eggs
Mass produced eggs or industrial eggs are the most common type of eggs in the market.These eggs are produced by chickens that are raised in small cages.
These chickens are fed a special diet that enables them to lay eggs for commercial purposes. The chickens are kept within a very limited area to ensure that many chicken occupy the least space possible.
Eggs produced this way contain nutrients that are limited to what the chickens are fed. In the event where the food fed to them is lacking some nutrients, the eggs produced by these chickens contain less nutritional value.
Free-range chicken eggs
Free-range eggs are eggs that are laid by hens that are allowed to roam around outside the barn or backyard.
Chickens that are raised this way eat worms and insects in addition to their grain diet.
Free-range eggs have been proven to have less fat and cholesterol thus reducing the risk of stroke and heart disease.
They also have more vitamin A, vitamin E and Omega-3 fatty acids. Vitamin A promotes healthy development of bones, soft tissue and teeth. It also promotes good vision and protects cells from damage. Vitamin E acts as an antioxidant and also promotes healthy blood circulation.
The Omega-3 fatty acids lower blood pressure and cholesterol levels. It also decreases the risk of stroke, digestive disorders, diabetes, dementia and some forms of cancer.
Here are are few other ways eggs are classified
Cage-free eggs are laid by chickens that are raised in floor systems, for example, an open barn. These chickens are usually in closed quarters but not in cages, therefore, they have room for ample movement. They are also given space to perch and their nests are usually made of hay or straws of grass.
Vegetarian eggs are laid from chickens fed on a vegetarian diet. That means that they are not fed any fish or meat by-products. These hens are normally kept indoors or in cages so that they do not peck any insects or worms.
Organic eggs are free from any inorganic materials. This is because the chickens that lay these eggs are not given any vaccines or antibiotics and are fed on a strict organic diet.
The food given to these chickens must be grown on land that has been free from the consistent use of pesticides and fertilizers for at least three years. The hens are also maintained without hormones, antibiotics or any other intrusive drugs.
All in all, we draw the conclusion that free-range eggs are of a higher nutritional value than mass produced eggs.
Hatching Chicken Eggs
As we have learned, a rooster is not necessary in egg formation. However, it is important to have a fertilized egg in order for hatching to take place. Typically, a chicken egg takes 21 days to hatch. There are two ways used to hatch eggs.
The first is the natural way and the second is by the use of an artificial incubator. When choosing eggs to set for hatching, ensure that they were laid within a period of ten days. When eggs have stayed for too long after hatching, their level of hatchability drops drastically. Pick out the eggs that are clean, even shaped and undamaged.
Once you are done, you can set the eggs for a broody chicken or place them in an incubator. Do not interfere with the eggs until they hatch if you set them for a broody chicken. This is because the chicken will refuse to incubate them any longer thus, the eggs will hatch.
However, when it comes to artificial incubators, you will need to turn all the eggs regularly especially during the first 14 days. If an egg is unturned, the embryo touches the shell membrane and sticks to it resulting to abnormal growth of the chicks. A mother hen turns the eggs on her own.
I hope that you have learned a great deal about chicken eggs. This knowledge will be great if you plan on keeping your own chicken in your backyard. You will now be able to appreciate those eggs that you might have taken for granted at one time or another.
Thanks for reading!
Steve M.