The outside of a chicken egg can be a huge range of colors but did you know the base shell color in domestic chickens can only be white or blue? It’s true! Brown chicken eggs are actually a white shell with tint over them and they are white – not brown – on the inside! Here are some pictures, graphics and tips on how egg shell interior colors can help you determine the genes your hen is carrying:
Egg Shell Interior Colors
There really are only two shell colors: white and blue. The presence of a single dominant blue egg gene means the hen will lay an egg with a blue shell base color.
How Other Egg Shell Colors Are Made:
Every other egg color is made by the hen’s body depositing a tint over the outside surface of the egg. Shortly before an egg is laid, hens who carry tint genes will deposit a coating on the shell that has the effect of coloring the egg:
13+ known genes code for “brown” tint. These 13 different genes can be turned “on” or “off”, which is what produces such a large range of brown tones. Some hens genetically inherit an extremely faint tint and lay cream eggs:
These same 13 genes, in different combinations, are also why some hens have very dark tints, like Marans, and lay dark chocolate or dark olive eggs:
Tints over Blue
The same tints over a blue egg shell produce different colors. A blue egg shell base plus a light tint produces sea glass bluey-green Easter Egger tones:
An egg with a blue shell base color plus a dark tint produces an olive egg:
Interior Shell Color is Useful
If you are not sure what base shell color a hen lays, crack open the egg shell and peel away the membrane to view the “base” shell color. The shell should be white inside of all cream and brown eggs or blue inside of blue and green eggs:
What About Heavy Bloom Eggs?
Since the bloom is deposited on the outside of the shell, it will not affect the interior shell interior. Heavy blooms can make it difficult to tell what the true color of the egg is until the outside of the shell gets wet.
Handy Genetic Shell Check!
If you have an olive egger hen that lays an egg that is so muddy brown you cannot tell if she is actually an olive egger or a brown laying olive egger, crack open her shell and peel back the membrane! If the interior is white, she is a brown laying olive egger. If the interior is a shade of blue – even faintly blue – she is an olive egger!
Are There Other Tips & Tricks I Should Know?
Experienced breeders have a technique they use to know which of their hens are going to breed the best colored layers and which are always going to produce lackluster offspring. This has been the useful secret behind the most incredible colored eggs you’ve seen online…and it is why you’re not getting the blinding blues nor the richest olives. If you’d like to learn the technique for yourself, check out our PDF titled Breeding for Egg Color From the Inside Out in our online shop!
Leave a Reply