You may wonder why anyone would need to perform an egg freshness test since most people raising chickens for eggs check the nesting boxes every day. If you have ever opened a rotten egg, you will never want to do that again! There have been two instances that required me to perform an egg freshness test to determine whether the egg was fresh, fertile or rotten.
The first situation was when my Black Australorp hen, Mammie, had been setting for about 16 to 17 days. I noticed she had rolled three eggs out of the chicken nesting box. I knew she would do that if the eggs were bad, but me being me I thought, “Well, she might not have meant to do that. Maybe she was just turning them and they flipped out.” So … I put the eggs back. The next day she had two of them out again. So I decided to check them and sure enough, they were rotten.
The second situation was when about half of my free-ranging backyard chickens were young hens. I thought they would see the older hens go back to the nest to lay and follow suit, but of course they didn’t. One day we were out moving some limbs and surprise! We found a nest of about 26 eggs. I had no way of knowing how long those eggs had been there, so I had to determine which eggs were good and which were bad.
I used the float test. While the float test is not 100 percent accurate, it has proven accurate enough for me. I use a 1-gallon bucket to do my float test. I fill the bucket 3/4 of the way full with water then add the egg(s) in question. Fresh eggs will lie on their sides on the bottom of the bucket. When an egg is a few days old, it will have one end that tips upward at a slant; if the egg is stale, it will stand on its end; and if the egg is rotten, it will float to the top. Any egg that floats in any way, shape, or form, I call it rotten. The way this works is that the air space at the large end of the egg enlarges as the egg ages and that airspace causes it to float.
The bowl test is considered to be the simplest way to perform an egg freshness test. Usually, a bad egg can be determined without completely breaking the shell. It’s harder to crack because the membrane has become tough. It will smell bad even from the outside and just as you barely crack it, stinky thick rottenness will ooze out. Some eggs are harder to determine by examining them and you just have to use the bowl test. You’re bound to get surprised from time to time. An egg that looks dirty and old will turn out to be fresh and one that looks fresh will turn out to be old. If the egg I crack open doesn’t have a funny smell, has good color, and the egg white is clear, I go ahead and use it.
But always use the mantra, “If in doubt, throw it out.” If you’re checking more than one egg at a time, be sure to rinse the bowl really well if a rotten one is found. One time my grandmother was cracking eggs and an undeveloped chick plopped out into the skillet. It was gross and smelled horrible. She said, “Well, that’s why I should be using a bowl.”
According to the old-timers, candling chicken eggs is the most reliable way to perform an egg freshness test. They tested the egg with a candle, that’s how the test got its name. The same effect is achieved by shining a powerful light through the egg while in a dark room. You can buy a candling station, but a good flashlight or even a candle will work in a dark room. Remember that the darker the egg shell, the harder it is to see. There is no way to tell if an egg is fertile or not without candling it. If the egg is fertile, you will see a spider like formation which is really just blood vessels forming. Personally, I don’t candle to determine fertility, I leave that up to nature. To perform the candle test, shine the light source next to the large end of the egg and you will see the inside of the shell illuminated. If the contents do not fill the shell, the egg is not exactly fresh. The larger the air pocket, the older the egg. In a fresh egg, the yolk doesn’t move about freely because the air space is small. In an older egg, the yolk will move around more freely.
So now you have an answer to ‘do eggs go bad?’ They definitely do, but these three egg freshness tests will help you avoid an encounter with a rotten egg. Personally, I’ve always used the float test, and I’ve never had a problem. Have you ever had a situation where you needed to determine if an egg was fresh or not? How about an experience with rotten eggs? I hope you find these tips useful. Be sure to share your experiences with us in the comments or by using the contact me page on our site. Be sure to check out all the other helpful articles you can find on The Farmer’s Lamp.
Originally published in 2014 and regularly vetted for accuracy.