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Why Do Backyard Chicken Eggs Have Brown Spots?

Why Do Backyard Chicken Eggs Have Brown Spots?

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Here we will discuss why backyard chicken eggs have brown spots. Keep reading to learn more.

If you are raising chickens in your backyard, it is a matter of time before you find an egg that will make you scratch your head and wonder how it was formed or whether it is damaged.

Usually, abnormal chicken eggs just happen. While they can indicate that your bird is stressed or sick, they are not necessarily something that should worry you a lot.

There are several abnormal eggs you will likely come across. While they may indicate a problem, they should not bother you so much.

The best thing you can do is to keep an eye on your flock for any signs of illness or stress. With a few exceptions, abnormal chicken eggs, such as those with brown spots, are okay to eat.

Chicken Eggs

Brown Speckled Eggs

Speckled chicken eggs are normal and have a pretty appearance. The speckles are extra calcium deposits formed when the egg formation process is disturbed or when there is a defective shell gland.

They can also result from excess calcium in your chicken’s diet. Although unique, they have the same nutritional value as regular backyard chicken eggs.

Therefore, they are safe to eat. Some studies have found that a speckled egg might be a way to make the shell stronger. 

Common Eggshell Quality Problems

Here are some common eggshell quality problems you are more likely to encounter if you raise chickens in your backyard.

White Banded Egg

A white-banded egg results from two eggs entering the oviduct and making contact with each other in the shell gland pouch. When it happens, the normal eggshell formation is interrupted.

The first egg that enters the pouch gets an extra calcium layer, which is seen as the white band marking. 

The main causes of a white-banded egg are stress and diseases, such as Infectious bronchitis. The best you can do is to keep an eye on your flock for any abnormal behavior.

Changes in lighting can also lead to a white-banded egg. An example is adding artificial lights in your chicken coop to encourage egg laying during winter.

Blood On Eggshell

This can be either a few spots, a smear, or an alarming amount of blood on the shell. It can be caused by cannibalism and vent pecking.

If your hen is pecked at the vent just before laying, the egg is likely to come out with some blood spots. 

Other causes of blood on the eggshell are a sudden increase in the length of daylight and an external parasite infestation around the chicken’s vent.

In addition, the condition can be caused by small blood vessels that have ruptured in the chicken’s reproductive tract from excessive straining.

This is common in overweight chickens and young chickens that are laying eggs for the first time.

Chicken Eggs

Body Checked Eggs

A body-checked egg is a result of an eggshell that got cracked during the egg formation process and had a calcium layer deposited on the crack before the egg got laid.

Some are covered by a thick calcium layer forming a noticeable band or ridge around the egg. 

Body checks can increase if your birds get startled early evening or late in the afternoon when the shell formation process begins.

The common causes of body-checked eggs are overcrowding and stress. The condition is also common among older birds.

Odd Shaped Eggs

Odd-shaped eggs are also referred to as misshaped eggs. They differ from the normal egg size or shape(or both).

An odd-shaped egg can be round instead of oval, too small, too large, or has major changes in shape. 

It can occur as a result of various things, such as defective shell glands, diseases like infectious bronchitis, and immature shell glands among young layers.

Other common causes of the condition are overcrowding in the coop, disturbances, and stress. 

Lack of Pigment or Uneven Pigmentation on Eggshells

This is a common chicken eggshell abnormality caused by various things. The causes can be:

Poor Nutrition

A deficiency in the main nutrients of a chicken’s diet, such as a lack of vitamins, protein, calcium, and other minerals, can have a negative impact on shell formation and color.

For instance, manganese, zinc, and copper help in transporting pigment onto the shell.

Therefore, a lack of these nutrients means uneven pigmentation on the shells. In addition, it is believed that magnesium can improve the eggshell color.

Viral Infections

Viral infections such as infectious bronchitis can lead to poor eggshell quality by causing a loss of shell color.

Other health issues that can cause damage to the reproductive system and lead to uneven pigmentation of the eggshell are avian influenza, egg drop syndrome, and Newcastle disease.

External and Internal Parasites

A heavy infestation of external parasites, such as red mites and lice, can have an adverse effect on the eggshell quality.

Also, a heavy infestation of internal parasites like roundworms and Capillaria worms can lead to pale eggshells.


Chicken Eggs

Some drugs, such as the coccidiostat drug, if present in your chicken’s feed, can interfere with eggshell pigmentation. 

Other factors that can contribute to uneven pigmentation on a chicken’s eggshell are physical stress, nutritional stress, environmental stress, and exposure to sunlight and high temperatures.

In addition, the age of the chicken can also affect the quality of the shell. Older chickens and those that have been laying eggs intensively over a long period tend to lay eggs with paler shells.

Shell-less Eggs

A shell-less chicken egg consists of a membrane, albumen, and yolk but does not have a shell. In this scenario, all egg contents are protected by the outer membrane rather than the shell.

The condition is common in pullets that are laying eggs for the first time. 

The causes are:

  • Immature shell glands in young chickens
  • Nutritional deficiency, i.e., lack of calcium and vitamins E, D, and B12. It can also be caused by a lack of selenium and phosphorous in a chicken’s diet. 
  • Stress can prompt the chicken to lay eggs prematurely before the shells are formed.
  • Extremely low or high humidity levels and exposure to very high temperatures.
  • An infestation of external and internal parasites, such as lice, mites, and worms.
  • Laying eggs while molting
  • Exposure to various toxins like bacteria, fungi, and mold.

Wrinkled Eggs

Wrinkled eggshells tend to have thinly creased or wrinkled surfaces. It can be a single small wrinkle or several large wrinkles.

The common causes of this eggshell quality problem are stress and disturbance during the egg formation process.

It can also be caused by defective shell glands and diseases like infectious bronchitis.

Corrugated Shell

A corrugated eggshell occurs when the membrane of an egg is thinner than normal, mainly because of double ovulation and having to stretch thinner to cover the extra content.

It leads to insufficient plumping of the egg, thus leading to a corrugated membrane onto which the eggshell gets deposited. 

The causes are:

  • Newcastle disease
  • Extra-large eggs, often because of double or multiple yolks.
  • Excess antibiotics
  • Excess calcium consumption
  • A defective shell gland
  • Deficiency of copper in a chicken’s diet
  • It can be hereditary
  • It is common in chickens recovering from infectious bronchitis.

Soft Shell Eggs

Soft-shell eggs are normally laid with an incomplete eggshell. In some rare occurrences, it can just be a thin layer of calcium. Its causes are the same as those of shell-less eggs. They include:

  • Diseases like avian influenza, infectious bronchitis, and egg drop syndrome. It can also be a result of external or internal parasite infestation.
  • Immature shell gland, especially in young hens that are laying eggs for the first time.
  • Laying eggs while molting
  • Eggs laid prematurely because of stress or disturbance during the egg formation process
  • High/low humidity and exposure to high temperatures.


If you have been wondering why your backyard chicken has brown spots, you are now answered.

The brown spots are extra calcium deposits formed when there is a defective shell gland or when the egg formation process is disturbed.

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