What Color was the First Chicken Egg?
Maybe shell color is less important than yolk color.
Many things have changed in the five and a half decades since my brother Albert ran his egg business on our Virginia farm out of a rehabilitated chicken coop. That chicken house was old enough to be made of Chestnut. The tree huggers among us know that lumber dated its construction to the 1920s, when the Chestnut Blight devastated our eastern forests. My first chicken-or-egg newsletter (https://www.someonegrewthat.farm/p/the-chicken-or-the-egg) covered the changes in egg production business models and those impacts on farmers since we had those chickens. Consumer preferences have also changed a lot.
Take eggshell color. In the late 1960s, Albert sold only white eggs. We ate any brown eggs from his flock ourselves, because his customers demanded white-shelled eggs. They thought that white eggs were better than brown eggs and they were willing to pay a premium for them. Most swore they could tell the difference on their plate without a bit of shell in sight. Grandad’s chick-hatching program soon became heavily biased toward white-egg producing hens as Albert’s egg business grew —much to my mother’s secret relief. Mom also suspected that the brown eggs were somehow inferior to the white ones. In our area, grocery stores sold only white eggs in those days. Albert’s flock was eventually all White Leghorns.
I’ve recently learned that egg color preference varied by region. My older New England friends tell me that they remember their local grocer selling only brown eggs in their youth. They associated brown eggs with freshness because their hometown Rhode Island Red hens laid brown eggs right there in New England. Other New England breeds, like New Hampshire and Plymouth Rock, also lay brown eggs. For New Englanders of a certain age, white eggs were for Easter egg dying and not much else, as they had to be shipped in from points far south and west. Not fresh—ick!
Sometime in the last fifty years, brown eggs became acceptable on tables which once saw only white eggs. In fact, brown eggs seem to have become downright fashionable even on tables outside of New England. I wonder if it was a halo effect when we recognized the health benefits of brown rice over white rice. Brown eggs now cost significantly more than white eggs at grocery stores in my area. I can’t help thinking about Albert’s customers demanding white eggs – and willing to pay extra for them – every time I buy eggs at a place with a choice of brown and white eggs and see that price difference.
Many studies have failed to correlate eggshell color with nutritional content. Brown eggs are not any healthier than white eggs. The brown color has nothing to do with the egg’s contents. The brown egg is completely formed as a white egg inside the hen. Some hens just have an extra step in their egg production. Right before she pops out that egg, the brown-egg layer coats it with a layer of brown color produced in her uterus (protoporphyrin IX, for you geeks). If her color distribution is abnormal, she may put some extra calcium spots on the egg, too, making them look freckled or speckled. As the hen ages, her eggs may be lighter brown. Some breeds have a pinkish tinge to this coating.
Take a look at the inside of a brown eggshell next time you crack one and you will see the brown color is superficial. Usually, you’ll see that the inside of the shell is white. White is the original egg color laid by the wild ancestor of our present-day chickens: Jungle Fowl. Calcium is, after all, white and eggshells are calcium. So, white eggs are the most “natural” eggs. Chicken experts call white eggs the “wild type.”
As a child, I thought that domestic chicken eggs came in only two versions: white and brown. If you wanted any other color egg, you had to go find a robin or some Easter-Egg dye. Nowadays, if you are shopping where Vital Farms’ True Blue or “Heirloom” eggs are sold, you can buy chicken eggs that have a bluish tinge to their shells. These blue shells have an origin and chemistry very different from robins’ egg blue. Domestic hens that have had a certain retrovirus infection lay blue eggs. That virus incorporates itself into the chicken’s genome during the infection. This mutation is heritable and dominant. It causes the hen’s liver to generate a blue pigment (Oocyanin) which influences the entire formation of the eggshell, so the blue color is not just superficial. You can see this blue on the inside of the shell. The offspring of these hens with virus-altered DNA will lay blue-tinted eggs even if they have never been infected. In a few generations, all the eggs laid by that genetic group will have that bluish tinge. So, there’s actually nothing “Heirloom” about those blue-colored eggs.
If blue-egg laying breeds are crossed with light brown-egg laying breeds, the offspring may lay green eggs. The hen’s light brown coating of the egg on top of the blue base gives it a greenish tinge. Crack these green eggs open and you will see the interior of the shell is blue. In the US, blue and green eggs usually come from hens with South American genetics, but the virus-caused mutation occurred independently in both South America and China.
During my early years, I also thought that the hen’s color determined her eggs’ color. In my limited experience, white hens laid white eggs and brown hens laid brown eggs. Simple, right? Later, my high-school friend Linda – who raised fowl of all types – introduced me to green and blue eggs. She did not have green and blue hens. Until I met her varied flock, I thought green eggs were something Dr. Suess made up. Introduction to her green eggs made me wonder what the green-eggs-and-ham fuss was all about. They looked the same in the skillet to me. I’ve been told that you can tell what color a hen’s egg will be by looking at her earlobes. Yes, chickens have ears, just behind their eyes, hiding beneath tiny feathers. Their earlobe is an area lacking feathers between their ear and their wattle. The egg color supposedly matches the earlobe color but that’s only true for the most common chicken breeds. Chickens laying green eggs don’t have green earlobes, for example. Somewhere along my way, I gave up on predicting egg color from chicken color. I just wait and watch the hen lay an egg to figure out what color her eggs will be.
Given the absence of nutritional difference correlated with shell color, why do brown eggs cost so much more than white eggs? One source says that applying the brown color requires extra energy, so the hen needs extra feed to color the egg. Other sources say that hens laying brown eggs are about 10% larger than hens laying white eggs. Larger hens need more feed. This farm girl thinks that’s a more plausible explanation for the higher cost of brown eggs than energy required to produce the pigment. So duh, most eggs produced in the US are white because they are cheaper to produce. Still, I am having a hard time visualizing enough extra feed to raise the price two dollars a dozen. In farm country, we call anything that allows us to charge more for the same product “selling the story” versus “selling the product.” An exercise for you, Dear Reader: Share your reason for paying extra for brown eggs in the comment section.
When buying eggs in the grocery store, I mostly buy cage-free eggs without regard for color. I get cage-free eggs despite a slightly higher price and somewhat higher risk of Salmonella compared with eggs produced in cage systems. Deadly Salmonella outbreaks traced to eggs in the early 1970s led to widespread adoption of cage systems for laying hens. No, cage systems weren’t introduced by some evil-empire industrial-agriculture complex trying to maximize exploitation of hapless hens for money. The cage systems result in cleaner eggs. Personally, I like the idea of the hens being able roam around the henhouse and perch and all that chicken stuff. Blame it on those childhood memories. I’ll explore the various systems (cage-free versus free-range versus pasture-raised) more in the next egg newsletter.
When I can, I get “farm eggs” from neighbors with laying hens. Those are usually colored as well as ungraded. I admire the variety of colors and sizes before I crack them, despite the extra effort of making sure I have the right amount of egg going into a loaf of bread. Gluten-free breads are especially sensitive to the amount of egg, so I use a scale to select the farm eggs for baking.
Honestly, tracking down farm eggs is a fairly recent effort for me – I had gotten into an egg-is-an-egg-is-an-egg mode for years until the pandemic left me facing empty grocery store shelves. My food allergies limit my protein sources, which left me very motivated to find eggs. I rediscovered chickens in that process. For a time, I rented an apartment from folks with a small flock. One of their Rhode Island Red hens took a liking to me. She would hop into my truck or follow me inside my apartment. She laid large, dark brown eggs. Sadly, lots of other critters – including birds of prey, coyotes, and foxes – like chicken for dinner, so her curiosity and freedom to roam did not end well for her.
My preference for farm eggs is actually based more on how the hens’ diet affects the inside of the egg than the variety of their shell colors. I can’t tell the difference between a brown- and white-shell egg or even a blue- or green-shell egg after they are in the skillet. But I can tell the difference between an egg from a hen eating greens and bugs and an egg from a hen eating corn and soy.
I don’t know exactly what the nutrient difference is, but a chicken is what she eats. If it’s not in her diet, it’s not in her egg. Some studies say that the foraging hen’s egg is higher in Omega-3s than the eggs of her grain-fed colleagues. I’m more interested in the color and consistency of the foraging hen’s egg yolk and its white before I cook it. This is the fault of both my inner cook and my inner environmentalist. My brother Albert long ago left his egg business for auto repair, but he still loves chickens. “A chicken can make something out of nothing faster than any other critter on earth,” he says. “That chicken scratches around what everything else leaves behind and grows and gives you an egg almost every day. And eventually, stew.” A more modern way of saying this is: Protein from chickens (eggs and poultry) has a low carbon footprint compared to other domesticated livestock. Foraging chickens have an even lower carbon footprint.
Chickens are omnivores – plants, bugs, even the odd baby mouse or mole can be their dinner. The yolk of an egg from an omnivorous, foraging chicken looks quite orange next to the yolk of an egg from a grain-fed chicken, which will be yellow. However, you can’t say that a foraging chicken was “vegetarian-fed.” That vegetarian-fed label on some grocery store egg cartons means 100% grain-fed, in contrast to a mix of grain and “rendered protein.” Parts of slaughtered animals and poultry that we humans don’t eat or feed our pets gets processed (“rendered”) into high-protein feed. This may include feathers, which are almost all protein. Feathers can be cleaned, pressure-cooked, and ground up for a high-protein feed additive called feather meal. Feeding feather meal is not as unnatural as rendered slaughter waste. Foraging chickens will eat stray feathers for the protein. A chicken grinds up feathers (and a lot of other things) in its gizzard. You and I chew our food with teeth to break it down into small pieces to make it easier to digest. Chickens don’t have teeth. They pick up some gritty sand in their travels and stash it in this muscular gizzard, which uses that grit to grind up what they gulp down. So, the average chicken has more, and truer, grit than any John Wayne character!
So what makes an omnivorous foraging chicken’s egg yolk orange? Why does an egg laid by a chicken fed grain and rendered protein have a yolk the same yellow color as a chicken fed grain only? Eating leafy green plants with lots of beta-carotene gives a foraging hen’s eggs the orange-colored yolks. I got a recent confirmation of this in my skillet. When my little feathered Rhode Island Red friend became prey, her people decided that it was too dangerous to let the rest of their flock outside anymore — and now those hens are laying eggs with yellow yolks instead of orange yolks. The avian flu risk right now is also keeping a lot of flocks indoors on feed mixes, so you may notice this change in your own skillet if you eat local farm eggs.
One hazard of getting eggs from your neighbor is: if there’s a rooster around, the egg may be fertilized. That will also put a spot of a color in the yolk. On our farm, my grandfather showed us how to “candle” a fertilized egg to see the shadow of the embryo developing inside: hold the egg up in front of a light. If there’s something blocking the light coming through the egg, it’s probably an embryonic chick. We actually used a flashlight instead of a candle, but the principle remains the same. It’s much easier to see through a white shell than a brown shell, making it easier to sort out the fertilized eggs as well as the older eggs. I think the greater visibility was a major contributor to that bias toward white eggs before egg processing was standardized.
Farm eggs might be fertilized, but you should be eating them before that embryo shows up with a candle. If eating or scooping a tiny bloody spot off the yolk freaks you out, then buy farm eggs from someone who doesn’t have a rooster or go back to the grocery store. In the US, those grocery-store eggs will be unfertilized. (I’ll get into why I say “in the US” in a future newsletter.)
US grocery store eggs are refrigerated from just off the farm to your grocery basket. Why? As the hen finishes forming the egg, she seals its pores with a protective protein film called the “bloom” or the “cuticle.” That film prevents bacteria from getting through the shell. It is nature’s way of keeping the egg clean inside while the chick develops. In 1970, in the wake of those Salmonella deaths, the USDA issued a regulation requiring that egg producers wash eggs right off the farm. The invention of high-volume egg-washers and dryers efficiently removed external contaminants including chicken litter. Water and sanitizing detergent dissolve that cuticle, so eggshells are left porous to bacteria and must be refrigerated.
During my recent trip to Germany, I was bothered at first by unrefrigerated eggs in the grocery stores. I then remembered that we didn’t refrigerate the eggs from Albert’s chickens when I was growing up. Our little Westinghouse refrigerator didn’t have enough room in it for those big baskets of eggs. We just waited to wash the eggs until we were ready to use them. And we all survived eating those unrefrigerated eggs. In Europe, the eggs are not washed before you buy them. European farmers vaccinate the hens for Salmonella. Their philosophy is: a hen infected with that bug can lay an egg with the bug inside it. It’s also cheaper to get the unwashed eggs to the consumer without refrigeration. They do mark every egg with its origin and date for safety and quality feedback.
When I get eggs from the neighbor’s backyard flock, I assume that they haven’t been washed and probably not refrigerated. I do put them in the refrigerator as soon as I get them to my kitchen, to extend their shelf life as long as possible. Refrigeration more than doubles the shelf life of an egg, even when unwashed. The unwashed, unrefrigerated egg lasts 21 days — the time it takes a chick to develop and hatch if the egg is fertilized. Refrigerated eggs can last up to 50 days, washed or unwashed.
I also test those backyard eggs for freshness before I use them, just as Mom taught me nearly sixty years ago. This test is an easy step toward washing them: just see if they float in a glass of water. The fresh eggs will sit on the bottom, both ends even, while the ones that you shouldn’t eat will float or peak above the water a bit, sort of like an iceberg. In between are the ones that will tilt up, one end a little higher than the other. The tilters are still okay to eat, but you will notice that the whites are runnier than fresher eggs, and usually totally transparent. What’s happening inside the egg over time? As our hen lays the egg and it cools, an air pocket forms at the more porous end of the egg. The chick needs this air space eventually to reposition itself and break out of the shell. As the egg ages, the shell becomes more porous. That pocket gets bigger as the egg loses moisture. If you have a bright enough light and an educated eye, you can see the air pocket through the shell and judge freshness by its size. For the rest of us who are not trained egg graders, the float test is easier.
During the pandemic, I re-discovered some egg preservation techniques, such as pickling eggs. This involves treating hard-boiled eggs almost as you would cucumbers, to make pickles. Hard-boil your eggs and peel them, then make a pickling brine of vinegar, salt, sugar, a bay leaf, garlic cloves, and any other spices you like. Submerge the eggs in the brine in an air-tight jar and put them in the refrigerator for a week. They keep quite a while – but leave them in the refrigerator unless you pressure-can them. I like to pickle some beets along with the eggs: the egg whites come out pink. Pink eggs are a guaranteed conversation starter.
Oh, and don’t use your fresh-off-the-farm eggs for this. Hard-boiled eggs are the one application where fresher is not necessarily better. We’ve all had the frustration of trying to peel an egg where the egg white clings to the shell. If the egg is only a couple days away from the chicken that laid it and unwashed, the egg white won’t separate cleanly from that membrane just inside the shell. The reason is also what gives the “white” of a fresh raw egg its milky character: carbon dioxide dissolved in the white. This makes the egg white pH about 7.7. Once the egg is washed, the shell is porous enough for oxygen and carbon dioxide to change places. The egg’s pH creeps up to about 9, considerably more “basic,” which helps the membrane and egg white to separate. So, wash that fresh egg and leave it in the refrigerator for a week – or buy the eggs you will hard-boil and peel from your local grocery store. Do the math: those eggs do not get from the chicken and through processing to your grocery store in less than a week. Especially since the chicken and the grocery store are probably not in the same state anymore. All that said, thermal shock still helps separate egg white from shell: plunge those eggs into cold tap water as soon as you remove them from the stove. Some people say that adding vinegar to the boiling water will make the egg easier to peel. I know vinegar keeps the white from coming out of cracks in the shells, but I can’t see how lowering the water’s pH would make the egg easier to peel. Please comment below if you can explain this.
A Navy submariner friend just told me about another egg preservation method: Water-Glassing. This was done by almost everyone before refrigeration and rural electrification (1930s in our area). This is how they kept eggs on the table during the winter months when the hens stopped laying. Apparently, mariners at sea on boats without refrigeration still use this technique, as you can preserve raw eggs for up to 18 months this way at very little cost. You must start with unwashed eggs – the “bloom” the hen coats the egg with must be intact. You submerge the raw eggs in a solution of pickling lime and water, cap the container, and store it in a cool, dark place. If you are getting eggs from a neighbor’s backyard flock and want to try this, volunteer to help them keep the laying boxes clean, so the raw eggs will be relatively clean. You want to preserve just the egg, not the chicken litter which contains bacteria — remember you can’t wash the egg first!
Speaking of bacteria, you already know that you shouldn’t eat an egg with any sort of crack in it that you did not put there. A crack in an egg is a path for bacteria to enter, even if the membrane is not broken. The inside of an egg is a perfect bacteria incubator. It’s not safe to eat more than a couple of hours after cracking. If you were the one who dropped the carton of eggs, you can safely have scrambled eggs for your very next meal, as long as you cook them solid. Use the “if it runs, I run” rule supplied by a friend who likes her eggs well-cooked, crack or no crack. Or use your egg-cracking accident as an excuse for an impulsive baking marathon—no bugs will survive the hour at 350F needed to bake that bread or cake.
We’ve all learned to make sure the eggs have no cracks at the store before purchasing them because you don’t know how long any cracks have been there. But what about feeding cracked eggs to your dog? An Indiana acquaintance explored this idea, hoping to prevent waste. To his surprise, his local grocery store was quite unreceptive to giving him cracked eggs for his dog. His grocer’s story: their wholesale supplier paid for them for returning the cracked ones, making them worth as much to the grocer as the whole ones. There’s another reason grocery stores don’t let any cracked eggs go out their front door: most states fine a grocer for each carton of cracked eggs they sell. You may have noticed your grocery-store cashier opening the egg cartons and checking for cracked eggs – this inspection is their final opportunity to avoid a fine. These fines may be $200 per dozen carton containing any cracked eggs sold, depending on the state. Ten years ago, a single cracked egg in a carton meant that the entire carton was condemned. Recent egg shortages resulted in some research and changes in the regulations. Grocers and wholesalers can now take the uncracked eggs out of a carton where eggs have been cracked and use those uncracked eggs for human consumption.
What else should you consider when you are buying eggs? Next time, I will delve into egg marketing and decipher more of the labels on eggs like “free range” and “pasture-raised” and “humane-certified.” And how some egg producers fake that “foraging hen” yolk color.
Statistics on chickens and eggs:
Diagram and explanation of an egg:
Anatomy of a Chicken Egg (scienceofcooking.com)
Egg Color:
https://www.huffpost.com/entry/brown-white-eggs-difference_n_5a8af33be4b00bc49f46fc45
Chicken Egg Colors: A Complete Guide (thehenhousecollection.com)
Are brown eggs healthier? Science debunks a pervasive myth (inverse.com)
Are Brown Eggs the Only Local Eggs? | The Brown Eggs vs. White Eggs "War of the Eggs" - New England
Blue Eggshell Mutation:
11 Chickens That Lay Blue Eggs — & Why {With Pictures!} (thepeasantsdaughter.net) (the light-read version)
An EAV-HP Insertion in 5′ Flanking Region of SLCO1B3 Causes Blue Eggshell in the Chicken | PLOS Genetics (the Geek version)
Feather Meal:
The Use of Chicken Feather Meal in Feeds - ScienceDirect
Chicken Gizzards and Digestion:
What Is a Gizzard and How Does It Work? - Cackle Hatchery
Pickling Eggs:
Classic Pickled Eggs Recipe (allrecipes.com)
{Old Fashioned} Pickled Eggs Recipe - Belly Full
Pickled Eggs in Beet Juice Recipe - These Old Cookbooks
Water-Glassing Eggs:
Water Glassing Eggs for Long-Term Storage - Backyard Poultry (iamcountryside.com)
Look up your state’s laws and regulations concerning sale of eggs:
State Laws & Regulations | The National Egg Regulatory Organization (nerous.org)
General Egg Safety:
Can I still use cracked eggs? – (eggsafety.org)
Egg-loving salmonella bacteria have been sickening people for decades — https://www.washingtonpost.com/wp-dyn/content/article/2010/09/13/AR2010091303594.html
Love your fascinating and well-researched articles, Kristin! As a non-Biologist, I have a vague understanding that a wide variety of environmental factors (including cosmic ray impacts!) can cause genetic mutations. But it hadn't occurred to me that blue eggshells originated from chickens getting viral infections!