Eggs with two yolks do exist, although they are very rare. We will reveal why some very specific eggs have two yolks and everything you need to know about it.
An action as simple and common as cracking an egg to fry it can bring us a curious surprise: two brand-new yolks in a single shell. Whether it is pleasant or disconcerting, the truth is that it is not common to find them. Why? What hens lay eggs with two yolks? How do you know if an egg has two yolks? Are there eggs with more than two yolks? Can eating them cause gastric problems or other health problems? Is it possible to buy them directly like this? In this article, we will clear up all doubts.
Why are there eggs with two yolks?
There are two different ways in which this can happen. But to explain them properly, we must first understand how eggs are formed. First, the nutrients supplied by the hen’s diet are then transmuted in follicles that grow in the ovary until they become, over the course of a week, a yolk of about 25 millimeters. This yolk moves for a whole day through the oviduct, during which time the bird can be fertilised by the service cock and during which the yolk is covered by the semi-transparent fluid that we all know as the egg white until it lands at its destination: the uterus, where the variable-coloured crust that is the shell matures.
Well, on certain occasions, the ovary releases a pair of yolks and not one, and both end up in a single egg after the aforementioned process. Or perhaps the first one gets stuck in the oviduct and ends up lowering later with the pressure of the next one and, likewise, inside the same shell.
Which hens lay eggs with two yolks?
There are no specific breeds of chickens among the 2,600 in the world that lay eggs with two yolks due to their special characteristics. In reality, we can discover them in anyone’s hair, and this is due to certain hormonal setbacks that can occur, regardless of whether they are moñudas, pirocas, bourbones, and so on. Perhaps, hereditarily, due to overfeeding or crossbreeding.
However, it occurs more frequently in young hens in their initial laying, due to their hyperactive and not yet fully regulated ovaries, or in older hens, when they are near the end of their reproductive life.
How to tell if an egg has two yolks
With pure observation, because two-yolked eggs tend to be larger and elongated, and their shell is more fragile, very different from those normally found in supermarkets; and weighing them, well, for obvious reasons, their mass is higher.
However, there is also an instrument to find out: the ovoscope, which is normally used by poultry producers to find out if the eggs have been fertilised after a week of incubation by the hen and, on the other hand, to monitor the correct development of the embryos, analysing the eggs against the light with a cold or LED light so that they do not suffer from excessive temperatures.
Can you eat an egg with two yolks?
Of course, there is no harm in eating them, and they are twice as nutritious as the yolks, with higher levels of an essential nutrient: water-soluble choline and vitamin A, which is important for a strong immune system and reproductive system, good vision and youthful growth.
The atypical event of coming across a double-yolked egg did not escape traditional superstition, and irrational relationships were established between this exceptional circumstance, good luck, nearby weddings, and the upcoming birth of twin brothers. But now the only concern is that they are beneficial to health or, at the very least, do not harm it.
How many yolks can a chicken egg have?
As calculated by the British Egg Industry Council, double yolk occurs in one in a thousand, in 0.1% of lays, therefore. And the probability of three in a shell is reduced to one in a billion, making this very natural rarity truly extraordinary.
In any case, the possibilities can vary between such a trio and no yolks at all. In the latter case, the eggs exist because a portion of reproductive tissue slips into the oviduct and the machinery continues its course until it obtains the shell that surrounds a tiny, hollow egg; a witch’s egg, as it is known; which, like those with two yolks, are more common in mature hens.
Buy two-yolk eggs
It is difficult to find them in ordinary shops because of their unusual appearance: distributors and traders prefer standardised eggs, with a similar appearance that makes it easier to classify and package them together and that does not displease customers, and they do not select them for sale or, in other words, they remove them during the classification process because they are usually larger and heavier.
If you want to play the lottery for this strange food, you must purchase it directly from the producers, on the farms or at the market stalls where they are sold. And, because industrial chickens do not have a very long “lifespan,” the phenomenon is more common in small towns and rural homes that raise and maintain layers for much longer. Especially if they are also considered pets.
But, if you prefer to play it safe and buy them directly, there is currently an online trade in eggs with two yolks and they can be ordered online and in establishments that specialize in delicatessens.