Should Eggs be Cleaned before incubating?

Should Eggs be Cleaned before incubating?

Whether hatching shipped eggs, your own, or your neighbor’s, cleaning eggs can be a dilemma that many face.
How dirty is too dirty?
Does cleaning harm the eggs?
Anxious breeders often ask these questions, and we’re here to help answer them.
The short answer is: only if absolutely necessary and with great caution. Cleaning can do more harm than good.

The Role of the Eggshell

Eggshells are one of nature’s many wonders. These seemingly simple barriers store calcium for the growth of the embryo, conduct heat, allow water evaporation, and regulate respiration. The most important job of the eggshell, however, is protecting its contents against injury or contamination. 

You can’t see it with your naked eye, but eggshells are covered in pores that allow oxygen to get to the embryo inside while carbon dioxide exits. This is also what allows the egg to lose weight during incubation.

The outer layer of the eggshell, also known as the cuticle, is the first line of defense for the embryo. If contaminants are able to enter the egg, no amount of cleaning will fix the problem.
So, for example, if an egg is laid in a dirty nest this gives viruses and fungi a chance to enter the egg through the pores, which are full of fluid in the first few seconds after an egg is laid.
Due to this, proper nest hygiene and frequent collection of eggs are crucial.

The Hygiene of Your Flock

If you are hatching your own eggs it is important to pay attention to the hygiene of your flock. We recommend a few simple steps to ensure the eggs that you are collecting remain free from contaminants. 

  • Train your flock to use their nesting boxes early on. This can be done by adding fake eggs.
  • Keep the nesting materials clean. Clean once a week for poultry and more often for waterfowl.
  • Gather eggs at least once a day or more often if possible.

If you do happen to collect a few dirty eggs, store these in a separate containing from the clean eggs to prevent cross-contamination.

Should You Clean the Eggs?

So now we get to the most important question: should you clean the eggs?
As we mentioned above, cleaning can do more harm than good in some cases, and here are a few reasons why.  

  • Sanitizing removes the outer cuticle from the egg, which leaves the egg at greater risk for bacterial contamination.
  • If done incorrectly, cleaning can actually cause the egg to become contaminated.

So then the question becomes, if you absolutely have to clean the eggs, how should you do it?

Proper Cleaning Procedures

There are two different cleaning methods, known as dry cleaning and wet cleaning. It should be noted that cracked eggs should not be wet cleaned, and they should be discarded if possible.

Dry Cleaning

This method uses abrasives to brush off lightly soiled eggs. Dry cleaning runs the risk of breaking the egg if not done gently. This is also a somewhat time-consuming method that weakens the cuticle of the egg. 

Abrasion creates a fine dust that can be pushed down into the pores, which can cause respiratory issues toward the end of incubation. If you use this method, sanitize the eggs from time to time with water and bleach and allow them dry fully before putting them in an incubator.

Wet Cleaning

This is a more complicated cleaning method that has gotten a bad name in the incubation world due to the issues it can create. The idea is that bacteria on dry eggs does not have the ability to get inside the egg, and wet cleaning gives it this ability. Bacteria passes through wet pores very easily compared to dry pores. 

The first thing that should be observed during wet cleaning is that the solution used to wash the eggs should be significantly warmer than the eggs themselves. Water that is colder than the eggs will flow inward through the pores and immediately cause contamination. Cooling the eggs causes the contents to shrink, which creates a vacuum inside the egg. This is what pulls the contaminated material inside the shell.

The ideal temperature for the solution is 105°F for washing and rinsing. After dying on a clean surface the eggs should only be handled with clean hands. 

Problems to Watch out For

If the washing solution you use is too hot or you immerse the eggs for too long this can damage the embryo. Warming the egg too much can cause the embryo to start developing at a slow rate so normal development cannot be sustained. Pay special attention to the temperature of the washing solution for small eggs. 

Conversely, if the washing solution is too cold it will shrink the contents of the egg and pull contaminated material inside the shell. This will also cause damage to the embryo, either from the cold solution itself or the bacteria it brings in.

It should be noted that while you can wash all eggs in the same solution, you should wash the cleanest eggs first and save the dirtiest for last. Best practice indicates that the washing solution should be changed regularly to avoid washing eggs with dirty water. 

Is it Worth the Risk?

When you take into consideration all of the risk associated with washing eggs, ask yourself if it is worth it.
If an egg is heavily soiled it may be better to discard it, especially if you are involved in a small scale production. 



Credits to the team at Brinsea for writing this article.

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