When it comes to egg color, birds display an amazing diversity. While chicken eggs may be the most familiar, coming in various shades of brown and sometimes white, avian eggs across species can be cream, pink, speckled, blue and even brightly pigmented. So what determines egg color? The answer lies in the genetics of the mother hen. Egg color is the result of pigments that are deposited as the egg develops in the oviduct. The two main pigments are protoporphyrin, which produces reddish-brown colors, and biliverdin, which produces blue and green hues. An absence of pigment results in white eggs.
Chickens
In chickens, protoporphyrin deposition is controlled by a dominant gene, while the recessive gene results in white eggs. This means white-feathered chickens that lack the dominant gene, like Leghorns and Anconas, lay white eggs. On the other hand, brown-feathered chickens like Plymouth Rocks and Rhode Island Reds that have the dominant gene lay brown eggs. This results in the common misconception that chicken egg color matches the feathers. While often true, this link can be misleading since breeds like Ameraucana and Araucana that have distinctive feather colors lay blue or green eggs due to biliverdin deposition.
Here is a table summarizing some common chicken breeds and their typical egg colors:
| Breed | Feather Color | Egg Color |
|---|---|---|
| Leghorn | White | White |
| Plymouth Rock | Black/white barred | Brown |
| Rhode Island Red | Red | Brown |
| Ameraucana | Black, blue, splash | Blue |
Ducks
In ducks, egg color is also genetically determined by the female. Wild mallards lay blue or green eggs, a trait dominant in their genetics. Domesticated duck breeds like the Khaki Campbell lay khaki-colored or white eggs based on selective breeding for this trait. Pekin ducks and other white feathered breeds lack protoporphyrin deposition and lay white or cream-colored eggs.
Some common duck breeds and their typical egg colors include:
| Breed | Feather Color | Egg Color |
|---|---|---|
| Mallard | Green | Blue/green |
| Pekin | White | White |
| Swedish | Blue | White |
| Khaki Campbell | Khaki | Khaki/white |
Geese
Goose eggs also vary in color between breeds. Wild geese like the Canada goose lay olive or brown eggs with a smooth surface. Domestic geese have been selectively bred for traits like white feathers and eggshell color. Breeds like the Pilgrim or Cotton Patch goose lay all-white eggs. Chinese and African geese produce creamy white eggs. Toulouse geese lay lightly speckled creamy eggs.
Here are some common goose breeds and their typical egg colors:
| Breed | Feather Color | Egg Color |
|---|---|---|
| Canada | Brown/gray | Olive/brown |
| Pilgrim | White | White |
| Chinese | Brown/white | Creamy white |
| Toulouse | Gray | Cream speckled |
Quail
In quail, egg color depends on the individual breed. Most common coturnix quail lay speckled, light brown eggs. However, breeds like the Texas A&M white quail, pharaoh or Manchurian golden quail lay white or cream-colored eggs. The genetics behind quail egg color are not as well understood as chickens but likely also involve protoporphyrin deposition.
Some quail breeds and their typical egg colors are:
| Breed | Feather Color | Egg Color |
|---|---|---|
| Coturnix | Brown/gray speckled | Light brown speckled |
| Manchurian Golden | Gold/brown | Cream/white |
| Texas A&M White | White | White |
Other Birds
While less common as laying hens, many other bird species also produce white eggs. Several species of pheasant including the Ring-necked pheasant, Green pheasant and Lady Amherst’s pheasant lay cream or whitish eggs with a smooth surface. Peafowl, including both peacocks and peahens, lay whitish or cream eggs that are faintly speckled. Small pet bird species like finches, canaries, and parakeets also lay plain white eggs if they are not pigmented for camouflage purposes.
Conclusion
In summary, white egg color is common across numerous bird species including chickens, ducks, geese, quail, pheasants, peafowl, and other exotic birds. White eggs result from an absence of protoporphyrin, the main pigment producing brown egg color. Selective breeding in domesticated fowl has favored white feathering traits that are genetically linked to white eggshells. So while feather color cannot definitively predict egg color across all breeds, white-feathered birds tend to lay white eggs due to shared genetics. The ability to lay white eggs likely evolved naturally in some wild species as camouflage but has been selectively propagated in domesticated fowl for consumer preference.