Stage 4 — week 16 and up
One property of a freshly laid egg explains almost everything about how to store it, and it is the thing washing destroys.
By Scooter M.·Published September 1, 2026
The short answer
A freshly laid egg carries a natural coating called the bloom or cuticle that seals the pores in the shell. Leave it intact and the egg keeps at room temperature for a long time. Wash it and the seal is gone, and the egg then belongs in the refrigerator.
An eggshell is porous — it has to be, because a developing embryo needs to exchange gases through it. Those same pores are a route in for bacteria. So a hen applies a thin protective coating as the egg is laid, sealing them.
That is why an unwashed egg keeps on a counter and a washed one does not. It is also why supermarket eggs in the United States are refrigerated and much of Europe’s are not: US commercial practice is to wash and sanitize eggs, which removes the bloom and commits them to a cold chain. It is a difference in handling, not in the eggs.
The practical rule follows directly: do not wash an egg until you are about to use it.
| Egg | Where | Note |
|---|---|---|
| Unwashed, bloom intact | Counter or a cool pantry | The traditional approach; keeps for weeks |
| Unwashed | Refrigerator | Also fine, and keeps longer still |
| Washed | Refrigerator only | The seal is gone; treat it like a supermarket egg |
| Cracked | Refrigerate and use quickly | Or discard if it has been in the nest |
| Frozen and cracked in the nest | Discard | The shell breach happened in a dirty place |
One rule that matters if you go the counter route: once refrigerated, keep them refrigerated. A cold egg brought out to room temperature condenses moisture on the shell, and moisture on a shell is a transport medium into the pores.
As an egg ages the contents lose moisture through the shell and the air cell grows. So a very old egg floats. Put an egg in water: lying flat on the bottom is fresh, standing on end is older but usable, floating is old.
What the test measures is age, not spoilage. A floating egg is not necessarily bad and a sinking egg is not necessarily good. It is a useful rough sort and the definitive test is still to crack it into a separate bowl and use your nose.
Almost every question about washing eggs is downstream of a nest problem. Eggs come in dirty because the nest is dirty, or because there is not enough bedding, or because a hen is sleeping in the box and fouling it overnight.
Fix those and most eggs need no cleaning at all: pads that stay put, boxes mounted below roost height so nobody sleeps in them, and — if it is a persistent problem — a roll-out box that gets the egg out of the nest entirely.
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Most of the egg-washing problem is a nest-cleanliness problem. Fixing the nest means fewer eggs ever need washing.
Precision Pet
13 x 13 in
Aspen excelsior fibers on a kraft-paper backing at a standard 13 by 13 inches, which is the size nearly every nest box is built around and the reason these are the default.
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Best Nest Box
24 x 19.5 x 20 in
The same roll-out mechanism in a two-foot box, which is the version that actually fits a backyard coop rather than a commercial layer house.
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Not until you are about to use them. A freshly laid egg carries a natural coating called the bloom that seals the pores in the shell; washing removes it and the egg then needs refrigeration. Brush off anything dry instead, and wash only the ones that genuinely need it, immediately before cooking.
Unwashed eggs with the bloom intact keep at room temperature for weeks, which is why much of Europe does not refrigerate eggs. Washed eggs need refrigeration. The one firm rule is that once an egg has been refrigerated it should stay that way, because condensation on a cold shell is a route for bacteria into the pores.
Unwashed and stored cool, several weeks; refrigerated, longer still. The float test sorts by age — flat on the bottom is fresh, standing on end is older, floating is old — but it measures age rather than spoilage. The definitive check is cracking the egg into a separate bowl and using your nose.
Dry first: a dry cloth or soft brush removes most soiling while leaving the bloom largely intact. If it genuinely needs washing, use water warmer than the egg — cold water contracts the contents and draws surface bacteria in through the pores — and then refrigerate it and use it sooner.
Every figure cited on this page came from one of these documents. If one of them has changed since we read it, the number here is out of date and we would like to know.
Nest boxes, roll-out designs, pads and sizing, plus what changes in the feed when the first egg arrives.
Why loose nest bedding fails, what the standard 13-inch pad fits, and the alternatives that work.
How a sloped-floor nest box removes egg eating as a possibility, and the level-mounting requirement people miss.
Nest boxes on published dimensions, with the one-per-four-to-five-birds ratio that decides how many you need.
The 18-to-22-week range, the physical signs that precede the first egg, and what delays it.