Did You Know There’s a Breed of Chicken That Lays “Chocolate” Eggs?

They look like chocolate eggs but they are very common eggs, with a shell, yolk and albumen like all the others you can find at the supermarket: we are talking about Marans eggs, or those laid by a particular breed that lives in France (the Marans, to be precise). In their homeland they call them "golden egg hens" (they cost around 3 dollars each). They are famous for their characteristic dark brown color given by protoporphyrin IX, a pigment derived from the metabolism of hemoglobin. This pigment is deposited on the shell in the last hours of the egg's formation, inside the hen's oviduct. Unlike other breeds of chickens, which produce white eggs or with lighter shades, Marans hens secrete a greater quantity of this pigment, giving the eggs a color that can vary from light brown to intense mahogany, up to a very dark reddish brown, almost chocolate. They had a huge worldwide success in the late 50s because they were mentioned by Ian Fleming in "From Russia with Love", the fifth novel of the James Bond series: they are the favorite eggs of the British secret agent (and of his author).

Marans Eggs' Characteristics

These eggs come from a breed originating from the French town of the same name located in the region of Nouvelle-Aquitaine (Bordeaux area to be clear). The hens are quite large and are particularly appreciated for their "aesthetics" but it is undoubtedly the color of the egg that makes them truly special.

The chocolate shade is not only an aesthetic feature but is also an indication of a chemical combination that is unique in the world. The color of the shell is determined by bile pigments that are deposited in the last stages of egg formation. The higher the concentration of pigment, the darker the final color will be. This characteristic also has a practical impact: the shell of Marans eggs is thicker than that of common eggs, offering natural protection against bacteria and external agents. This makes them safer from a hygienic point of view and prolongs their conservation compared to conventional eggs. The content is also different compared to "canonical" eggs. The yolk is denser, creamier and more intense in color thanks to a higher concentration of beta-carotene. They have a richer taste and a more velvety consistency than the eggs of common hens. However, this also depends on the hen's diet and not only on its biology. Marans in France are very pampered and usually eat grass, proteins, insects and high-quality cereals. Nutritionally, Marans eggs are considered more nutritious than standard eggs. They contain higher amounts of omega-3,  a higher content of B vitamins, higher levels of antioxidants and high-quality proteins. Because of all these peculiarities and the rarity of the hens (especially outside France and the United Kingdom) they usually have a very high cost: each egg costs about 4 dollars.