Guide to Backyard Eggs

When hens reach maturity and begin laying eggs their bodies take time to adjust to the laying cycle and as a result their first eggs are small.

Laying Eggs

Chicken eggs come in a variety of colors and sizes depending on the breed of the chicken.

Photo by © 2017 Chris Cone

Content Tools

Learn all about raising backyard chickens from small beginnings with chicks and eggs to identifying problems within backyard flocks and how to fix them in Pam Freeman’s Backyard Chickens Beyond the Basics (Voyageur Press, 2017).  Freeman’s practical advice makes chicken keeping easier with these guidelines. The following excerpt is from Chapter 4, “All About Eggs."

You can purchase this book from the Capper's Farmer store: Backyard Chickens Beyond the Basics.

Once your chickens are finally old enough to lay eggs, it’s exciting to head out to the coop and check the nest boxes to see if you’ve gotten any eggs that day. Your days are filled with anticipation!

When the first egg came from my first flock, I was so excited. I’d been waiting and checking the nest boxes every day. My hens had started squatting as I walked up to them, so I knew eggs were imminent. And then suddenly there it was! I remember grabbing that egg and running inside to show my family. We all stood around the egg and admired it.

We debated whether to keep that egg or cook it. In the end, we couldn’t resist tasting it. So I took a picture for posterity’s sake, then we cooked it and we all had one bite. It was delicious and we were forever hooked on the creamy flavor of the backyard egg.

Over the next few days, we received more and more eggs. I gathered up a dozen and decided the extras should go to the rest of our family. When my dad came to pick some up, I immediately opened the egg carton and preened over the beauty of my fresh eggs. My dad, who grew up in the city, just stood and looked at the eggs. I asked him what was wrong. He asked why they were smaller than store bought eggs. I explained that chickens lay small eggs when they first start laying but not to worry because they get bigger over time. He looked at me and said that was fascinating. He took the eggs home but looked befuddled as he was leaving.

I got a call from my mom that night. She asked what I had told my dad about those eggs. Apparently he had taken the eggs to my mom and told her not to worry that they were small, to just leave them in the refrigerator for a few days and they’d get bigger. He told her he never knew eggs grew!

It took me a second to realize what my mom was telling me. My dad thought that eggs them-selves grew in size once they were laid until they reached the size you see in the stores. My mom was laughing so hard she almost cried. She explained to my dad that when an egg is laid, it doesn’t grow in size. Hens that are just getting into the swing of laying, lay smaller eggs until their bodies fully adjust to the laying cycle.  My dad seemed relieved by this information and has remained fascinated by my chickens. He loves the eggs they produce.

Beyond loving the eggs backyard chickens produce, this chapter takes fresh eggs to another level of understanding by exploring exactly how eggs are formed inside a hen, how eggs get their color, which chicken breeds lay colored eggs, the parts of an egg, and how to properly store eggs. This chapter will take the ordinary egg and make it extraordinary. You’ll never look at an egg the same way again!

Egg Formation and Egg Color

Nowadays, as more people get into backyard chicken keeping, interest in the different egg colors and the breeds that lay them has increased. Many folks raise different breeds of chickens just for the color of eggs they lay! There’s nothing wrong with this. In fact, it’s downright fun to collect an egg basket full of colored eggs. There are so many egg colors to choose from: white, brown, olive green, dark chocolate brown, and blue.

Just how eggs get these unusual colors and whether or not they taste different are questions many chicken keepers have. We’ve all heard people say brown eggs taste better than white eggs. We’ve also seen people look at green and blue eggs and ask how they taste. I actually even hear it from chicken keepers themselves: they will swear that one color egg tastes different than another. They associate egg taste with shell color.

To understand how an egg is formed is to understand how egg color is applied—and why it doesn’t affect taste. From this, you can see that he flavorful parts of an egg are intact before the eggshell is ever formed. Taste comes from what a hen eats and the freshness of the egg.

Tip: With some exceptions, you can generally tell what color egg a chicken will lay by looking at its earlobes. White lobes equal white eggs.

How Eggs are Formed

When a female chick hatches, she already has fully-formed ovaries, which contain all the reproductive cells (called ova) she will ever need to lay eggs. She has tens of thousands of ova contained in her ovaries. As she grows, her left ovary matures and becomes her only functional ovary. Each ovum has the potential to form an egg and is contained within a follicle, which is attached to the ovary. Once a hen is mature, she has the capability to begin laying eggs. At maturity, her body starts to add yolk to the ova. You can think of it like a production line, with a layer of yolk being added to the first ovum on day one.

On day two, another layer of yolk is added to the first ovum and a layer is added to the next ovum. This goes on down the line until the first ovum is mature and ovulation takes place. About 99 percent of the yolk is added in the seven to nine days before ovulation. At ovulation, the follicle surrounding the ovum ruptures and releases the yolk into the oviduct and the 25-hour process of forming an egg begins. The oviduct, a canal where the rest of the egg is formed, is about 25 inches long and has five distinct areas where different parts of the egg formation take place: the infundibulum, magnum, isthmus, shell gland, and vagina.

The first stop for the yolk is the infundibulum, a 3- to 4-inch funnel, which catches or engulfs the released ovum. The yolk spends about 15 to 30 minutes at this point where the chalazae are added to keep the yolk in the proper place in the middle of the egg. If you have a rooster, this is where the egg is fertilized. Regardless of fertilization, egg formation continues.

The yolk then moves down the oviduct to the magnum, a 13-inch-long area where the egg white forms, and then to the isthmus, a 4-inch-long area, where it is covered by the inner and outer shell membranes. This process in these two areas takes around four hours.

How Color Comes In

From here, the forming egg moves into the shell gland where it will spend approximately the next 20 hours with the eggshell being formed around the inner contents. All eggs start out white because they are formed of calcite, which is a crystallized form of calcium carbonate that’s naturally white. If you have a white egg–laying chicken, then no pigment is added after the shell is formed. If you have a blue egg–laying chicken, the blue pigment, oocyanin, is added here and sinks through the entire shell—so the outside of the shell and the inside of the shell are blue. If you have a brown egg–laying chicken, the brown pigment, protoporphyrin, is applied fairly late in the shell formation, after the white base has been laid. Because it’s applied so late, the brown pigment does not penetrate through the shell, leaving the inside of a brown eggshell white. For a green egg–laying chicken, the process is a little more complicated. It starts with the blue pigment being applied, followed by brown pigment. Since the brown pigment is applied late in the process, it doesn’t sink through the entire shell, but it does mix with the blue on the surface to create green. The darker the brown pigment, the darker the green.

In the vagina, the bloom, or protective covering, is added to the egg. As the egg travels through the oviduct, it travels small end first. In the vagina, the egg is turned and moved to the cloaca where it is laid large end first.

Fun Fact: Near the shell gland and the vagina is the sperm host gland. This gland’s sole purpose is to promote reproduction of the species. When a rooster mates with a hen, his sperm is stored here. When an egg is laid, a small amount of sperm is squeezed out of this gland and then travels up to the infundibulum where it can fertilize the next mature ovum. Sperm can live in the host gland for about two weeks. Hens can actually choose whether to keep sperm or not. Hens can “dump” sperm from a lesser rooster in favor of that from a lead rooster.

The cloaca in both hens and roosters is where the digestive, excretory and reproductive tracts all come together. So that a hen cannot lay an egg and defecate at the same time, the shell gland

stays wrapped around the egg while it moves through the cloaca. This shuts off the intestinal opening as the egg is laid.

Once you’re familiar with how an egg is formed, simple math outlines a hen’s laying cycle. After a hen lays an egg she will ovulate in the next half hour or so. Since the entire egg laying process takes 25 hours then she will lay an hour or so later the next day and so on. Eventually a hen will skip a day or two from egg laying to catch up. This composes a laying cycle and can vary from 12 days to almost a year depending on the breed of hen. Today’s commercial hens are bred to have very little time between egg laying and ovulation, thus speeding up the process and producing more eggs during their laying cycle.


Chicken History

For many backyard chicken keepers, it’s all about the eggs: those nutrition-packed gifts from our hens. Nowadays, if you want to move those eggs from place to place, you stuff them into a card-board or plastic egg carton for quick and easy transport to your family, friends, and customers. But it wasn’t always like that.

In the early 1900s, eggs were just as sought after as they are today, and folks needed some way to safely transport their eggs. In 1903, a patent was issued for a wooden egg carrier with a removable cardboard insert and a metal slider that could join multiple stacks of carriers. These carriers were made by the manufacturing company of John G. Elbs with the STAR trademark. An advertisement from 1909 for the Star Egg Carrier shows that by then these carriers were really catching on:

“Savages carry eggs home in their hands or mouth. The Farmer’s Wife makes the round of the mow, mangers, and hen house and carries the eggs home in her apron. That’s no reason why you should use the old fashioned Paper Bag or Pasteboard box. Wake up! Join the procession. Star Egg Carriers mark the progressive store.”

Star Egg Carriers solved the problem for local trips to buy eggs, but what if you didn’t live close? In Fredericksburg, Virginia, in 1913, ordinances were passed that banned livestock, including back-yard chickens, in the city for public health reasons. At the same time, similar ordinances were being passed throughout the country. People still needed fresh eggs and farmers had an abundance of them.

Inventor Stuart Ellis came up with the solution to connect farmers and city folk. He created a metal box that contained rows of cardboard bent into the shape of an egg and supported at the top and bottom with metal edging. Eggs were placed large end down, with tissue paper under and above.

The top of the metal carton had a rectangular cut out for the receiver’s address. Inside were elaborate instructions on how to pack the eggs. These instructions were double-sided and had a place to write the receiver’s address on each side. The egg buyer could send the empty carton back to the farmer with the flip of a sheet and vice versa. Pretty efficient!

There are all kinds of advertisements in seed magazines and early poultry magazines in the 1920s selling these crates, which held up to six dozen eggs and started at 85 cents each. They took advantage of the Parcel Post that allowed people to send crates, and not just letters, directly to each other.


Breed and Egg Color

An egg collecting basket full of different colored eggs is achievable by picking the right breeds. There are lots of breeds to choose; many that are perfect for backyard chicken keeping and especially for families with kids. Below is a list of commonly found chicken breeds organized by egg color.

Colored Eggs
• Ameraucana (blue/green)
• Araucana (blue)
• Cream Legbar (blue)
• Easter Egger (green/blue)
• Oliver Egger (dark olive to light teal)

Brown Eggs
• Australorp
• Brahma
• Cochin
• Delaware
• Dominique
• Faverolle (light brown)
• Jersey Giant
• Naked Neck Turkens
• Marans (dark brown)
• New Hampshire
• Orpington
• Penedesenca (dark brown)
• Plymouth Rock
• Rhode Island Red
• Sussex (cream/light brown)
• Wyandotte

White Eggs
• Andalusian
• Ancona
• Appenzeller Spitzhauben
• Campine
• Catalana
• Fayoumi (tinted)
• Hamburg
• Lakenvelder
• Leghorn
• Minorca
• Polish
• Sicilian Buttercup
• Sultan
• Sumatra


The Parts of an Egg from Outside to Inside

If you’re lucky and you observe an egg just after it’s been laid, you may notice it looks wet. That’s because as a hen lays an egg, the very last addition is the bloom. This is a protective layer that starts out wet but when it’s dry it protects the egg from dust, dirt, and bacteria. The bloom is critical to keeping the contents of an egg safe because the shell, while hard, is actually semi-permeable and allows air and moisture to pass through its more than 17,000 pores.

The shell is 9 to 12 percent of the total weight of an egg and is made primarily of calcium carbonate along with magnesium carbonate, calcium phosphate, and other organic matter.

Once inside the shell, you will find inner and outer membranes, which are another line of defense against bacteria. These membranes are made of keratin and separate as the just-laid egg cools to form an air sac, usually at the large end of the egg. When peeling a hard-boiled egg, you can usually find this spot. When the membranes separate, the outer layer attaches to the shell and the inner layer surrounds the egg white or albumen.

Next comes the egg white, which makes up about 60 percent of the egg’s weight. If you break a fresh egg in the frying pan, you’ll be able to see that the egg white comes in two parts: the thin outer layer and thicker inner layer. The thick layer in a fresh egg is cloudy. This layer is a major source of riboflavin and protein. Over time it thins and becomes indistinguishable from the thin layer.

Also inside the whites of an egg are two chalazae. These are twisted cords that anchor the yolk in the center of the egg; the fresher the egg, the more prominent the chalazae. The cords are edible, although some people do remove them when cooking dishes that need to be perfectly smooth.

Last but not least is the yolk, the yellow portion of the egg. The yolk is held together by the vitelline membrane. The yolk accounts for at least 33 percent of the egg’s weight and is packed with nutrition: proteins, vitamins, and minerals including iron, vitamins A, B, and D, phosphorus, calcium, thiamine, choline, lutein, folate, and riboflavin.

The color of an egg yolk is not an indicator of the nutrition value of an egg. Color is determined by what a hen eats. If she eats more foods higher in xanthophyll, a naturally occurring yellow pigment, then her egg yolks will be richer in color, sometimes almost orange. Many commercial foods contain marigold petals, which are high in xanthophyll. Other xanthophyll-rich foods include green leafy plants, corn, basil, pumpkins, carrots, peaches, prunes, and squash. The reason many backyard chicken owners find their egg yolks richer in color is because their chickens are more apt to free range and consume a varied diet that’s high in xanthophyll.

Fun Fact: If you look closely at the surface of the yolk of a raw egg, you may see the germinal disc. This is a small spot, only 2 to 3 millimeters, where the sperm enters the egg. This is where the embryo develops and sends out blood vessels into the yolk for nutrition. The germinal disc is a solid white spot and is hard to see in an unfertilized egg, but in a fertilized egg it is referred to as a bull’s-eye and is more prominent since it’s a spot with a white outline and a clear center.

More from Backyard Chickens Beyond the Basics:

The Fundamental Backyard Chicken Coop


Reprinted with permission from Backyard Chickens Beyond the Basics by Pam Freeman and published by Voyageur Press, 2017.

Buy this book from our store: Backyard Chickens Beyond the Basics