reading time: 4 Session minutes
Story and pictures by Chrisley Johnson While I was going about my morning duties in the barn, I was met with an extraordinary surprise. An unfamiliar colored egg has found its way into one of my nesting boxes. I was used to seeing almost every shade of brown from the eight hens, but I had never seen one with a perfectly white eggshell.
This discovery led me to search for more information regarding such a drastic color change. Was it the result of a disease? Just a weird egg thing that happens from time to time? I was determined to understand what exactly was going on with my plane.
Understanding how eggs are formed inside my chickens has been crucial to my investigations. Get ready to be educated.
formation of eggs
The formation of eggs begins inside the hen in the form of an egg, more commonly known as the yolk. The yolk is formed much like a human egg is formed by the ovulation process in the ovary.
From the ovary, the yolk makes its way to the funnel of the oviduct called the Infundibulum. This is where the egg has the opportunity to fertilize. The yolk then continues its journey to the magnum where it captures the contents of the egg white or albumen.
Before the eggshell is formed, the yolk and white are transferred to the isthmus. It is in the isthmus where the inner and outer shell membranes are created. This membrane gives the chelae (white, rope-like strands) something to adhere to in order to stabilize the yolk as well as act as the basis for eggshell formation.
The uterus or shell gland is the longest pause in the egg formation process, totaling approximately 24-26 hours. Calcium is extracted from the tissues of the chicken’s body and deposited on the membrane that envelops the yolk and albumen. At this late stage, the egg receives its shell coloring before being laid.
Eggshell colour
Simply put, eggshell coloration depends on genetics. Depending on the breed of chicken or crossbreed, eggs can range from white to green to dark brown and every color in between. While all eggs start out white, some results depend on when the eggs were exposed to the dye.
For example, Ameraucanas produce ocyanin early in the process causing a bluish color to appear throughout the entire shell. Brown egg layers of different strains deposit their colouration, caused by protoporphyrin, at the caudal end of shell formation. This results in a crust that is white on the inside and brown on the outside. Olive eggs lay eggs with a mixture of both dye methods. The result is an egg that appears olive green.
Causes of anomaly
Abnormalities like my egg white are technically caused by a very short stay in the uterus during the last stage of shell formation. This is also supported by the porous feel of my white hair. While it was hard to bear to go through the hatch, the overall safety seemed a little compromised.
Stress is the number one cause of most atypical eggs in healthy hens. Temperature fluctuations, plumage, and yes, even the initial stages of a minor illness can stress a bird to the point where its eggs are affected.
Many young birds under the age of one year can put up a crazy number of things. Double or triple yolks, no shells, wrinkled eggs, no yolks and other weird things like my egg white.
Early laying hens expelled dots of shellless eggs with only thick whites or small eggs during the first month of production. The gray egg in this picture is a duck’s egg.
Many of my little eggs either have very little yolk or no yolk at all, as seen in this poached egg.
Dark, wrinkled eggs can be the result of a hen’s diet having too many eggs in her oviduct.
One of my little girls laid a very large chicken egg (right), larger than a duck egg (center) and a medium chicken egg (left).
In short, most eggshell color changes are not a cause for concern unless the situation persists. The same applies to deformed or abnormal eggs. If it is persistent, then you should probably look for stress factors such as illness or nutritional deficiencies. Indicators such as eggshell quality, yolk color, and even albumen consistency can give you insight into the health and condition of your flock.
To learn more about what happens here on the farm and what I learn as a first-time herd owner, visit my Dirt On My Plate website.