Last updated: September 2026
Quick answer: Shell colour is genetic and fixed for each hen’s whole life. Every egg starts white. Blue comes from biliverdin laid down through the entire shell; brown comes from protoporphyrin painted onto the outside at the end; blue shell plus brown coating produces green or olive. Shell colour has no effect at all on taste or nutrition.
How egg colour is actually made
Every egg shell begins as calcium carbonate, which is white. Everything else is pigment added on the way out, and the timing of when each pigment is applied explains almost everything about egg colour.
The egg spends around 20 hours in the shell gland. Two pigments can be added during that window:
Biliverdin produces blue. It is incorporated throughout the shell as the calcium is deposited, which is why a blue egg is blue all the way through. Crack one open and the inside of the shell is blue too. Biliverdin is a bile pigment, chemically the same compound that makes a bruise turn green.
Protoporphyrin produces brown. It is applied at the very end, painted onto the outside surface in the last few hours before laying. This is why a brown egg is white on the inside of the shell, and why brown pigment can be scrubbed or scratched off a fresh egg.
From those two facts everything follows:
| Base shell | Brown coating | Result |
|---|---|---|
| White | None | White egg |
| White | Light | Cream or tinted |
| White | Medium | Brown egg |
| White | Heavy | Dark chocolate brown |
| Blue | None | Blue egg |
| Blue | Light | Green or mint |
| Blue | Heavy | Olive |
The blue gene, called oocyan, is dominant, which is why crossing a blue-egg bird with almost anything produces coloured eggs. It originally came from South American chickens, primarily the Araucana.
Breeds by egg colour
| Colour | Breeds | Notes |
|---|---|---|
| White | Leghorn, Ancona, Andalusian, Polish, Hamburg, Minorca | Mediterranean breeds; usually the heaviest layers |
| Cream / tinted | Silkie, Faverolles, Dorking | Very light brown wash |
| Light brown | Rhode Island Red, Sussex, Australorp, Sapphire Gem | The standard backyard brown egg |
| Medium brown | Orpington, Plymouth Rock, Wyandotte, New Hampshire | Classic dual-purpose breeds |
| Dark brown | Welsummer, Barnevelder, Empordanesa | Welsummer eggs often heavily speckled |
| Chocolate | Marans (especially Black Copper), Penedesenca | The darkest eggs in poultry |
| Blue | Ameraucana, Araucana, Cream Legbar | True blue; blue right through the shell |
| Green | Easter Egger, Isbar | Blue base with a light brown wash |
| Olive | Olive Egger (a cross, not a breed) | Blue base with heavy dark brown |
| Pink | Some Easter Eggers, Barred Rock, Light Sussex | A heavy bloom over a light brown shell |
Two clarifications worth making. “Pink” eggs are not really a pigment, they are a thick bloom layer over a pale brown shell giving a pinkish cast. And Olive Egger is not a breed, it is a cross between a blue-egg bird and a dark-brown-egg breed such as a Marans.
If coloured eggs are the goal, the practical route is a few Easter Eggers for blue and green plus a Welsummer or Marans for dark brown. Full profile of the most available coloured-egg bird is in our Easter Egger guide, and output figures across breeds are in the best egg-laying breeds.
The earlobe rule
An old and surprisingly reliable shortcut: look at the hen’s earlobes. White earlobes usually mean white eggs; red earlobes usually mean brown eggs.
The link is genetic rather than causal. The genes controlling earlobe pigmentation sit near those affecting shell pigmentation, so they tend to be inherited together. Leghorns have white lobes and lay white eggs; Rhode Island Reds have red lobes and lay brown.
The rule breaks down on blue-egg breeds. Ameraucanas and Easter Eggers have red or reddish lobes but lay blue and green eggs, because the oocyan gene works independently. So the earlobe test tells you white versus brown, and nothing about blue.
Does colour affect taste or nutrition?
No. This is one of the most persistent myths in backyard poultry, and the research is unambiguous. Shell colour has no relationship to flavour, nutritional content, shell strength or yolk quality.
What people are actually noticing is real, but it comes from somewhere else. Backyard eggs often do taste better and have deeper orange yolks than supermarket eggs, and that is down to diet, not shell colour. Hens with access to grass, insects and varied forage produce yolks richer in carotenoids, which is what makes them orange, along with higher omega-3 content.
A brown supermarket egg from a caged hen and a white supermarket egg from a caged hen taste identical. A blue egg from a well-fed backyard hen and a white egg from the same flock also taste identical. It is the feeding that matters, which is covered in what chickens eat.
Brown eggs cost more in shops for a purely practical reason: brown-egg breeds are larger birds that eat more feed per egg produced. The premium reflects production cost, not quality. Consumer guidance on egg grading and safety is available from the USDA Food Safety and Inspection Service.
Why colour fades over the laying cycle
A detail most people notice but few can explain. A hen’s eggs are usually darkest at the start of a laying cycle and get progressively paler as the cycle continues.
The reason is that each hen has a finite capacity to produce protoporphyrin, the brown pigment, over a laying cycle. Early eggs get a generous coating. As the cycle goes on, the supply thins, and eggs come out lighter. After a molt and the rest that goes with it, the pigment supply is replenished and the first eggs of the new cycle come out rich and dark again.
This is most obvious in Marans keepers, who often find the deep chocolate eggs of early spring have become ordinary mid-brown by late summer. It is completely normal and not a sign of anything wrong.
Other things that temporarily lighten shell colour: stress, heat above 85°F, illness, and age, since older hens generally lay paler eggs. A sudden dramatic change in shell colour or texture, though, is worth investigating alongside the causes in why chickens stop laying eggs.
Can a hen change egg colour?
Not fundamentally, no. A hen that lays blue eggs will lay blue eggs for life. A brown-egg hen never starts laying blue.
What does vary is shade. The same hen may lay a rich brown egg in March and a pale one in August, for the pigment-depletion reason above. Green eggs may look mintier or more olive at different points. But the underlying colour, which is set by genetics, does not change.
This is why nobody can promise you what colour a young Easter Egger pullet will lay. It is determined at hatch and revealed at point of lay, typically 20-26 weeks, as covered in when chickens start laying eggs.
Making olive eggers
Straightforward genetics that you can do at home, and the reason so many backyard flocks now include olive layers.
Cross a blue-egg parent with a dark-brown-egg parent. The blue gene is dominant, so the offspring lay a blue-based shell, and they inherit heavy brown pigmentation from the other side. Blue underneath plus dark brown on top gives olive.
| Cross | Result |
|---|---|
| Ameraucana x Black Copper Marans | Deep olive, the classic pairing |
| Cream Legbar x Welsummer | Olive, often speckled |
| Easter Egger x Marans | Olive, but less predictable |
| Ameraucana x Welsummer | Mid-olive, often speckled |
The darker the brown parent, the deeper the olive. F1 birds give the most reliable results; breeding olive eggers to each other produces increasingly variable colours. You will need a rooster for any of this, and the practicalities are in do chickens need a rooster.
The bloom, speckles and oddities
The bloom, or cuticle, is a thin protein layer applied to the outside of the shell as the egg is laid. It seals the roughly 7,000 pores in the shell, keeping bacteria out and moisture in, and it is why unwashed eggs keep so well at room temperature, as explained in how to store fresh eggs. Washing removes it. It also affects appearance, giving a matte finish and sometimes that pinkish cast.
Speckles are uneven deposits of brown pigment, most characteristic of Welsummers and Marans. They are purely cosmetic and often prized.
Occasional oddities that are usually harmless: a chalky white overlay from extra calcium deposited late; a “sport” egg of a noticeably different shade, often after a stressful day; wrinkles or ridges from a disturbance during shell formation; and blood or meat spots inside, which are small ruptures or tissue fragments and are entirely safe to eat.
Repeated soft, thin or shell-less eggs are a different matter and point to a calcium, vitamin D or health problem rather than a pigment quirk.
Frequently asked questions
What determines the colour of a chicken egg?
Genetics alone. Every shell starts white, then biliverdin may be deposited through the shell to make it blue, and protoporphyrin may be painted on the outside to make it brown. Blue plus brown produces green or olive.
Do brown eggs taste different from white eggs?
No. Shell colour has no effect on taste or nutrition. Differences in flavour and yolk colour come from the hen’s diet, not from the shell.
Can one chicken lay different coloured eggs?
No. Each hen lays a single colour for life. The shade can vary through a laying cycle, but the underlying colour never changes.
Why are my brown eggs getting lighter?
Each hen has a limited supply of brown pigment per laying cycle, so eggs get paler as the cycle progresses. Colour returns to full depth after a molt. Heat, stress, illness and age also lighten shells temporarily.
Which chicken lays the darkest eggs?
The Black Copper Marans lays the darkest eggs in poultry, a deep chocolate brown. Penedesenca, Welsummer and Barnevelder are the next darkest.
Are blue eggs blue on the inside of the shell?
Yes. Biliverdin is deposited throughout the shell as it forms, so a blue shell is blue all the way through. Brown pigment is only a surface coating, so brown eggs are white inside the shell.
What breed lays green eggs?
Easter Eggers most commonly, along with Isbars. Green results from a blue shell base with a light brown coating over it.
Does egg colour change with the hen’s age?
Shades tend to lighten as hens get older, and egg size increases. The base colour itself stays the same throughout her life.
Want a rainbow basket? Read the Easter Egger profile for blue and green layers, and browse every breed we cover in the chicken breeds guide.