raising happy, healthy chickens

What is the Bloom on an Egg

About 5 months ago I wrote a post on egg facts. And in it I mentioned that pasture-raised eggs can last months, as long as they haven’t been washed, because of the bloom. But what is the bloom on an egg? Well, back then I didn’t get into it.

The Bloom: Nature’s Armor

The bloom, or cuticle, is a protective layer that the hen’s body deposits on the outside of the egg just before she lays it. You might be curious to know that eggshells have around 8000 microscopic pores between the calcium carbonate crystals forming the shell. And the pores permit moisture, gas, and bacteria to pass between the inner and outer eggshell.

brown and blue abstract painting that depicts bacteria
Photo by CDC on

So nature has this defense against contamination, which is the bloom. And it prevents bacteria from transferring from the outside of the egg to the inside.

To Wash or Not?

However, if you wash eggs, or buy store eggs which are washed, this protective layer is removed. According to NPR, there was no standardized way to wash eggs 100 years ago, although many people naturally did so. Then people got sick; Europe and the U.S. couldn’t agree as to what to do. So in the 1970s the USDA developed a way to clean eggs, that all commercial producers here have to adopt.

But once eggs are washed, they have to be refrigerated, because then they are susceptible to bacteria. Maybe you’re aware that Europe doesn’t wash their eggs. Though their poultry are vaccinated against Salmonella, whereas the USDA doesn’t require our birds to be. Additionally Europe’s eggs aren’t refrigerated, due to the intact cuticle. Thus, both methods are working toward the same goal: preventing people from getting food-borne illness, specifically Salmonella.

chicken eggs placed in wicker basket on table
Photo by Nida on

Should you wash your eggs? Personally, we don’t until it’s time to cook or use the egg(s). However, that being said, we’ve had some eggs that looked disgusting. Like a duck that smashed an egg and got some other eggs sticky. Or the same duck just likes to make a mess out of laying her own eggs. In the first case, the only thing to do is clean the egg(s) with water. And in the second case, it just depends on how bad of shape the egg(s) are in whether we would need to clean them.

Guidelines Regarding Washing and Refrigerating Eggs

  • If purchasing eggs from the store, always keep them refrigerated. They no longer have the bloom.
  • Though, if you buy your eggs from a farmer, ask if they washed the eggs. Due to the difficulty peeling fresh-from-the-hen eggs, you’ll definitely want to leave some eggs on the counter for 4-5 days before boiling if you want hardboiled eggs. That’s because fresh eggs are just too fresh. But if not, refrigerate them, because they’ll definitely last longer.
  • Commit to the course! If you refrigerate, don’t take them out and leave them on the counter, because they’ll start to sweat, making the bloom disintegrate, and bacteria can get in. Trust me! This happened to me. And all I can say is, yucky!!
2 egg cartons, creamer, and other food items in refrigerator

This next part is for people like me, who have chickens and ducks, and need to know reasons for cleaning eggs. Because most of the time, you don’t need to wash them.

At this point, a lot of sites would refer you on how to clean the chicken coop. And perhaps that might help. But my husband faithfully cleans our coop monthly; and I mean, the big clean-up that most people save for twice a year. (I suppose he just wants something to do.)

Reasons for Dirty Eggs

We’ve had some really dirty eggs before. However, I can honestly say that it wasn’t due to the coop being messy. And we’ve never had over 30 birds. Even now, we only have 27 chickens and 4 ducks.

2 dirty brown eggs
Feathers, straw, and even chicken poo can sometimes get on the eggs.

But we have had some birds that would just make the biggest messes on their eggs. However that was most likely due to their diet. Also, it never lasted more than that one day, though it made an icky mess. So then all the eggs in that nest needed to be cleaned.

Since having chickens, and learning so much about them in 7 years, I can report that dirty eggs aren’t as common as they once were. Except regarding the ducks.

Ducks ALWAYS dirty their eggs. It’s in their nature, it’s what they do, and it serves a purpose. Though I don’t know what that is. And I’m not the only duck farmer who has observed this behavior. (Of course, there could be a genius duck guru who knows why ducks do what they do. Or God. But no one has informed me as of yet.) Anyway, we have this Pekin, Bakugo, who lays her eggs, dirties her eggs, and all of the other eggs in the nest.

several blue dirty duck eggs in a nest
This clutch of eggs actually belongs to our Mallard, Aizawa.

Other possible reasons for dirty eggs: sick birds, roosts too close to the nesting boxes, or nesting boxes without roofs. Also, the hens could be scratching out the hay, straw, or pine shavings from their nesting boxes. I like this suggestion from the-chicken-chick. She recommends extra padding in the nesting boxes with empty feed bags, or something similar. That way if the nesting material gets scratched out, the eggs will still be on a padded surface.

So then, if you get really dirty eggs, what’s the best way to clean them?

How to Clean Eggs or Get Clean Eggs

Well, don’t get out the soap and water just yet, because you still want to try leaving the bloom intact. First, determine how often you’re gathering dirty eggs. If it’s once in a while like us, then proceed to the following steps.

But if you’re getting dirty eggs on a regular basis, you may need to change their diet, or inspect your flock for illness. Especially if the coop is in tip-top shape, with nesting boxes secure from roosting birds. And once you’ve sorted them out, do the following:

  • Collect eggs more often

If you’re collecting eggs multiple times a day, the chances that you’ll get nasty eggs that need to be cleaned decreases.

  • Add sand to floors of the run and coop
grayscale photo of sand
Photo by Jonathan Borba on

This is another recommendation from the-chicken-chick to avoid collecting dirty eggs. As a litter material, washed construction sand has many benefits dating back decades. But the main point here is the birds walk across it and, it sort of is like a scrubbing doormat, wiping off soiled feet before any hens get in the nests to lay eggs.

  • Dry washing

I typically use this method most often. And you can use your fingers, if it’s just dirt. Or a paper towel if it’s feces. Usually it comes off very easily, so long as you collect eggs frequently.

  • Sandpaper

If, however, you forgot to collect the eggs, you might find that the dirt or other has hardened onto the eggshell. So try sandpaper. But avoid coarse sandpaper, because it can easily strip the cuticle. McMurray Hatchery recommends .320 grit.

  • Water
close up shot of a person washing an egg on running water
Photo by cottonbro on

When you’re ready to use the eggs, it’s recommended to wash them, making sure the dirt and feces are completely removed. And one of the best ways is with actual warm water, but never soak the eggs. And don’t use cold water, because that could actually cause bacteria to go below the surface of the eggshell, while warm water does the reverse; it draws it out of the shell.

These are the best ways to clean eggs while trying to leave their natural defense untouched. That’s because it’s without chemicals that can be leeched into the eggs themselves.

Thanks for stopping by! And if you enjoyed this post, please like, comment, share, and please don’t forget to follow!



I breed pure Black Ameraucana chickens and Easter Eggers that are Black Ameraucana mixed with either Cuckoo Maran or Barred Rock. And I donate eggs to people or organizations in need.

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