This website is reader-supported. When you buy through links on our site, we may earn a small affiliate commission.

What Causes Egg Abnormalities?

Last Updated: 25.02.24


Especially in the case of farm hens that are kept in a specially designed chicken cage, the risk of laying abnormal eggs is considerably higher, due to the multitude of possible causes out there. Stress, viral and bacterial diseases, unbalanced feeding diets or improper lighting are just some of the most frequent causes of egg abnormalities.

There are many factors that influence the quality of the eggs produced by hens, regardless of their breed, causing abnormal eggs to appear in the nest. The better the flock caregiver can identify the source of the problem, the easier it becomes to correct it, so that it does not become a major issue within the flock of hens.

In case the problem persists, even though changes in the daily routine, diet, and care have been made, it’s best to seek out veterinarian expertise and treatment, as it may be an infectious disease causing the egg abnormalities. If left untreated, the disease can spread within the group of hens kept together, causing serious financial loss.

It is of utmost importance to take immediate action, when egg abnormalities are spotted in the nest, to prevent any further implications and possible loss of valuable hens. Thus, let’s take a closer look at some of the possible causes of egg abnormalities and the most efficient ways of correcting them in due time.


The age of the birds

Sometimes, the bird caregiver may spot unshelled eggs in the nest, which are considerably smaller than normal eggs are. This is usually correlated with either very young hens that are just now starting to lay their first eggs, or very old hens, that are in the last days of their egg-laying career. Both of these situations are normal and the former will get corrected in due time.

Unfortunately, hens do not usually live to see the last days of their egg-laying time, so unshelled smaller eggs are a sign of very young birds that are just laying their first eggs. Any responsible caregiver will know for sure which birds in their flock the about to lay their first eggs, based on their age, and will not get alarmed by their presence. 

However, if this situation persists, then further inquiry is needed, as it may be the case of a viral or bacterial disease within the flock, as young birds will only lay one or two unshelled eggs in the first week and after that, they will lay optimum-sized, normal eggs, according to their breed. Unshelled eggs are quite common in egg-laying breeds, as they start early.




Stress is considered to be the main cause of egg abnormalities in chickens. Overcrowding, improper feeding, improper lighting, lack of fresh air, lack of free movement, roosters that are too big and heavy, or too many roosters compared to the number of available hens are just some of the stress causes, and the most common ones, within the flock.

Any of these stress causes will have a direct translation into abnormal eggs, such as yolkless eggs, unshelled eggs, misshapen eggs, or eggs that look like they have been cracked and then stitched back together with calcium. Besides the financial loss that these abnormal eggs cause, they are the first sign that there is something very wrong with the hens.

Another sign of high levels of stress in hens is that they stop laying eggs completely in a time of the year when they are supposed to be most active. Such an event is a serious cause for concern and immediate action should be taken, as hens may fall ill because of that. One needs to accurately spot the stress cause and remove it immediately.


Viral and bacterial disease

Viral and bacterial infections within the flock are another possible cause of egg abnormalities. They are usually associated with other clinical symptoms, so it’s quite easy to determine when there is more going on than just stress. Some of these symptoms include lack of appetite and movement, possible diarrhea, changes in the comb’s color and shape, or coughing. 

The egg abnormalities most often seen in viral and bacterial infections are pale-shelled eggs, soft-shelled or shell-less eggs, and wrinkled eggs. Most of these abnormalities can appear in other situations too, such as feeding disorders, stress or diets lacking certain minerals and vitamins, or lighting disorders that have been going on for a long time.

However, when you have these abnormalities associated with other clinical signs too, it’s best to seek out veterinarian check-up, a proper diagnosis of the cause and appropriate treatment as soon as possible. Also, keep in mind that eggs coming from ill hens should not be handed out for human consumption, under any circumstances. 


Feeding disorders

It is of utmost importance to hens, and chickens in general, to receive a balanced diet according to their age, production purpose and time of the year. For instance, when hens start laying eggs again, in the springtime, it is highly advisable to add calcium and vitamin C and D to their diet, as they are using most of their own calcium and vitamins to produce many healthy eggs.

On the other hand, feeding them high calcium levels in the wintertime, when their calcium consumption is considerably lower due to the fact that they have stopped laying eggs altogether, may come as a mistake, as their bodies will deposit the extra calcium in all the wrong places, such as their articulations or oviduct, compromising their lives.

It’s important to know and understand how their bodies and metabolism work, according to their age and breed, thus offering them the best possible diet that will ensure they live healthy lives and produce high-quality products for as long as possible. This way we also ensure we do not suffer any major financial loss, making the most of it.


Lighting problems

It is a widely known fact that birds are light-dependent animals, and that they thrive when the light to dark hours ratio is the optimum one. One thing that many people do not know is that you can actually make a hen lay more or larger eggs by prolonging her active hours with extra light hours, by using artificial light.

This used to be a widely used practice in large industrial chicken farms, both meat and egg-producing ones, as caregivers would turn on the light inside the farm for a few more hours. The direct result was more eggs in egg farms and chickens that grew faster and heavier in meat farms. It took a while for the downsides to show up too.

In the case of egg farms, one of the first drawbacks of this practice that showed within the farm was egg abnormalities, both shape and content-wise, as hens started laying more eggs than they were supposed to, but were unable to provide the same quality eggs as before. This practice was stopped at some point, and now they are only allowed one to two extra light hours per day.



Prevention methods

To prevent most of the possible egg abnormalities from showing up in your hens’ nests, there are quite a few things you can do about it. One of the first things to take into consideration is never introducing new birds into your group of chickens without a previous quarantine period of at least two weeks. 

Feeding them balanced feeding formulas, with added calcium, minerals and vitamins in the spring and summertime is always a perfect way of preventing any unwanted egg abnormalities. Also, adding vitamin C to your chickens’ diet will help them stay healthy as it stimulates their immune system and helps them fight off viruses and bacteria.

Making sure you avoid overcrowding in your flock is of utmost importance, as it may result in high stress levels in your birds which will automatically result in ill birds and abnormal eggs. Even if you think that for short periods of time it may work for them, think again, as their immune system drops dramatically in stressful situations, and this may result in financial loss. 

Moreover, in the case of free-range chickens, making sure you keep the proper ratio of adult roosters to adult hens is also very important. This is especially hard to do when you have growing chickens that develop very quickly and you are faced with the situation of young roosters that are too young to sell, but too old to be kept together with your hens.


Leave a comment

0 Comments Protection Status