Know Your Eggs! The Insides Of Chicken Eggs, Explained!

Know Your Eggs! The Insides Of Chicken Eggs, Explained!

How well do you know your chicken’s eggs?


Eggs can tell you a number of things about your hen’s health – for example, whether your hen is stressed or even sick.


So it’s important to know about the different parts so you have a baseline, and if you plan to HATCH eggs, knowing them gets even more important!


As chickens evolved, their eggs developed for reproductive purposes, ot eating, so each part of the egg contributes to whether the embryo will hatch or not.


Here’s the different parts of an egg and what you need to know about them!



Air Cell

The air cell is located in the large end of the egg, and it’s what it sounds like – a place where air is stored.


When you hatch eggs, the air cell and its size becomes very important. As an egg ages, the air cell becomes larger, which is why older eggs float in water..



When we talk about “egg whites,” we’re referring to the albumen. It’s full of proteins, niacin, riboflavin, magnesium, potassium, and sodium.


A cloudy albumen means the egg is fresh. As the egg ages, the carbon dioxide escapes, leaving the albumen more transparent than their fresh counterparts.



This is the round white bullseye-looking spot you see in the yolk, and it’s where embryo begins to develop when the egg is fertilized and under hatching conditions (meaning, the egg is at the right temperature with the right humidity for hatching.)



The bloom of an egg is a natural coating that covers the eggshell and protects the interior of the egg from bacteria. It also reduces moisture loss from the egg, which is important for the hatching process.  


If you plan to hatch your eggs, you definitely don’t want to wash them, because it will eliminate the bloom.



Pronounced kah-layz-ah, the chalazae are the rope-like strands you see connecting egg whites to the yolk. The more obvious the chalazae are, the fresher the egg.


In nature, it’s an important part of the hatching process because stabilizes the yolk (which feeds the chick embryo as it grows) in the egg.


Membrane, Inner & Outer

The inner and outer membranes provide more protection for the eggs contents. The air sac is located between these two membranes on the large side of an egg.



The shell protects the albumen and yolk, and eventually the growing embryo. It’s mostly made up of calcium carbonate, which is why feeding your chickens a calcium supplement is so important. The shell is also made up of thousands of pores to allow gas exchange.


Vitelline Membrane

This membrane protects the yolk and keeps it from breaking. It weakens as the egg gets older, which is why yolks of fresh eggs stand up tall, while yolks in older eggs appear flatter.



The yolk is a protein and vitamin rich portion of the egg, and where the embryo begins developing in a fertilized egg. It’s also where 100% of the fat in eggs is contained.


Just before chicks are born, they absorb the yolk, which nourishes them for up to 3 days.


Curious about egg abnormalities like wrinkled shells, rubber eggs, and lash eggs? the carbon dioxide escapes


Do Eggs Go Bad? How Long Do Eggs Last? Here’s What You Need To Know!

Do Eggs Go Bad? How Long Do Eggs Last? Here’s What You Need To Know!

We all know fresh eggs are best, but what about whether they spoil? Do eggs go bad? Can eggs go bad?? How long do eggs last??

 Yes, eggs can go bad, but do you know WHEN do eggs go bad or how long do eggs last? In this article, I answer all these questions.

We’ve made the mistake every so often of forgetting that we left eggs on the counter, or one of the kids hid an egg in an undisclosed location. We’ve always found them eventually – and it’s not been a pleasant find.

When eggs rot, not only do they stink – they turn black and gooey. It’s really an experience you’re better off not having.

In this article, I’m going to show you how you can keep your eggs as fresh as possible, how you can tell if eggs are bad, and answer the age-old question “how long do fresh eggs last?”

Do Eggs Go Bad? Here's What You Need To Know!

Why Do Eggs Go Bad?

Eggs go bad even when they’re refrigerated – they definitely have an expiration date. It’s not usually the date printed on the carton (if you happen to have bought eggs at the store – if you did, consider getting chickens).

How long do eggs last? It can take quite a bit longer for eggs to go bad, but they will, beyond a shadow of a doubt, spoil. When eggs are laid, they’re covered with something called “the bloom,” a cuticle or natural covering that keeps bacteria out of the egg, keeping it fresher for longer.

It’s an evolutionary advantage that helped chickens reproduce successfully – and egg that can easily be contaminated won’t hatch or will hatch weak and sickly chicks.

Store-bought eggs (at least in the US) have had the bloom removed – so if you’re wondering “how long do eggs last?” not only do eggs go bad, store bought eggs will rot faster, even when refrigerated. This is because they’re more susceptible to bacteria entering through the shell and contaminating the albumen (egg whites) and the yolk. Not a good thing!

Farm fresh eggs – that haven’t had the bloom removed – will still spoil, but at a slower rate.

Do Eggs Go Bad? Here's What You Need To Know!

How Do Eggs Go Bad?

As the bacteria enters the egg, it will reproduce and grow, feeding on the nutrients – particularly if you’ve left the eggs on your shelf and not in the refrigerator.Eventually, so much bacteria gets into the egg that the insides turn black – and very stinky. Learn more about the insides of a chicken egg.

If you wonder “how can you tell if eggs are bad,” there’s a few different ways. Does it pass the smell test (in other words, does it stink)? If you smell anything – just toss it. Fresh, healthy eggs don’t smell at all.

Another option is the Egg Float test – you can learn how to that in this video:

How Long Do Eggs Last Unrefrigerated?

You might be wondering how long you can leave eggs out before they become rotten. There’s a few different answers to this questions. Fresh eggs with the bloom on can last quite a while – 2 to 3 weeks. However, they WON’T be fresh or as healthy for you..

You’ll notice the air sac at the “fat” end of the egg is larger. You’ll also notice, when you crack them, that the yolk might be runny (this is because the membrane holding the yolk together weakens over time) and the albumen (egg whites) are clear – all signs that your egg is no longer fresh nor as nutritious.

So how long do refrigerated eggs last? According to the United States Food Safety and Inspection Service, part of the USDA, which has also answered the question “do eggs go bad?,” refrigerated eggs can still be refrigerated 4-5 weeks after their expiration date – so for fresh but refrigerated days, they can last up to 2 months inside the refrigerator.

If you want to preserve fresh eggs for long term storage, here’s an article that shows you how.

How long are eggs good for: Conclusion

So, if you’ve been wondering “do eggs go bad?” or “how long do eggs last?” you can feel quite sure that as long as you leave the bloom on and keep them in a cool area, they’ll last quite a while.

How long do eggs last at your house? Have you ever cracked open a bad egg? Tell me all about it in the comments below!

More Chicken Egg Resources:

The Backyard Chicken Bundle is a unique ebook bundle with every resource you need to start raising a flock of healthy hens! (Total value $250) Included in the bundle are:

  • 5 individual ebooks with over 40 gorgeous full color photographs, charts, and recipes for all-natural coop cleaners, layer feeds, herbal first aid salves, and more.
  • 34 page Herbal Encyclopedia to growing 30 different herbs for your hens right in your own backyard
  • 3 downloadable checklists to save your flock from bad weather & predators, and to keep them healthy while molting.
  • 1 Apple Cider Vinegar for Backyard Chickens video that shows you step-by-step how to make organic apple cider vinegar in your own kitchen
  • Information you can TRUST by a recognized backyard chicken expert featured in Reader’s Digest, Glamour, and on major news networks like ABC, CBS, & NBC.
  • And START spending every possible minute playing with & enjoying your pets (without the worry)!

Get your Backyard Chicken Bundle here!

Backyard Chicken Bundle