Your Chicken Questions Answered by a Veterinarian. Honest and Practical Advice

Chicken Egg Shell Problems You Must Know About And How To Fix Them

If you have only ever purchased eggs, you have probably only seen perfectly uniform eggs in each tray. Smooth, evenly-colored, hard shells all lined up, every egg clean and neatly presented. It can therefore be a shock to find misshapen or blood-stained eggs inside your chicken coop. You may even occasionally come across an entirely shell-less egg!

As a veterinarian, my curiosity peaked when I had my first egg shell problem (a soft-shelled egg). I started to research why there are chicken egg shell quality problems, how they are caused and how to fix them.

No-one can drink from an empty cup, and it is the same for our hens. What you put in is what they are able to deliver, so keeping chickens in top condition is vital to ensure that the eggs they produce are healthy and perfect. Fortunately, chickens are uncomplicated birds, and keeping them happy isn’t difficult.

Read on to learn all about chicken egg shell problems.

Chicken Egg Shell Quality Problems And How To Fix Them

If you are a chicken owner, you know the feeling of anxiously anticipating the arrival of your first, glorious homegrown egg. Young hens seem to take forever to lay, and the first egg you spot in the coop is always a super exciting find. 

What is essential to understand is that some egg quality problems are unavoidable, so even the best cared for hens may occasionally produce a peculiar egg. Chickens aren’t machines, and their bodies change with age. Like everyone, they may sometimes have an off day; for example, if they are stressed while laying, they may produce a long, skinny egg instead of a distinctive oval shape.

Several factors will affect the consistent production of good quality, well-formed eggs. Four main components determine overall egg quality:

  • The shell
  • The albumen – that is the white part of the egg
  • The yolk
  • The overall composition of the egg

For such a small item, plenty of oddities can occur in any of these four elements. Let’s go through the causes of egg quality problems, how to identify them, and most importantly, how to remedy them. You will never crack an egg into the pan again without first appreciating how perfectly it is formed!

An Egg Is An Egg – What Could Go Wrong?

Because eggs are produced by living creatures, plenty of factors can affect how they turn out. The overall quality and quantity of eggs will be affected by the following eight factors:


There are a lot of avian diseases that will have a profound effect on egg production and quality of eggs. Diseases affect the overall health of the chickens – infections, even from the respiratory system, can spread to a bird’s ovary and oviduct – which will ultimately affect egg quality.

Age Of The Hens

The incidence of undersized, misshapen, or all-around weird eggs is more commonly found in hens at the beginning or end of the laying cycle. Chicken owners with pullets that have just started laying may occasionally find a ‘fairy egg’ – perfectly shaped mini-eggs.

A fun bit of information about these tiny yolkless eggs that are occasionally produced by pullets at the start of their laying cycle is that in times long past, there was quite a bit of superstition attached to them!

The tiny eggs were believed to be eggs of a dreadful serpent-like creature. The only way to safely dispose of these small ticking landmines was to fling them over the family home (without touching the roof), so they smashed to smithereens on the other side. There must have been lots of pressure on the thrower to get it over!

A 2016 study on commercial layers concluded that hen age is the major factor that affects the quality of fresh eggs. Progressive deterioration had occurred in the thickness of the shell, albumen, and color of the yolks in the hens measured at 60 weeks of age as opposed to hens that were half their age.

Environmental Factors 

Backyard chicken owners need to be particularly aware of this. Chickens may seem happy-go-lucky, but they are incredibly sensitive to factors like overcrowding, pecking order, and even things like boredom.

Chickens that are stressed show a reduction in laying performance. Stress affects every part of a chicken’s health. It not only makes them more susceptible to diseases but can also result in behavioral issues, like egg eating or messing inside laying boxes.


Although temperature also falls under environmental factors, it is so critical that it needs a heading of its own. Hot hens will experience an increase in egg quality-related issues. Chickens fare far better in cold climates than when they are hot.

The effects of heat stress on laying chicken has been shown to affect egg production and the quality of the eggs. Heat also includes issues like poor ventilation. Chicken owners should ensure that coops remain as cool as possible during heatwaves.


While chicken variety does not seem to play much of a role in terms of the actual nutritional quality of eggs produced, the size of eggs and the number of eggs produced varies significantly between breeds. That is why commercial laying farms use only particular hybrid varieties that will lay a high volume of large eggs.

Factors like eggshell color is also primarily determined by a chicken’s breed. Green eggs may actually be on the menu in your home if you have Olive Eggers! While factors like diet, age, and environment can cause slight variations in the shade of eggs produced, the overall determinant is a hen’s breed.


In order to remain healthy and produce consistently high-quality eggs, hens need enough of the right nutrition. Egg shells, in particular, are high in calcium, and data suggests that laying hens should receive a diet that contains around 3.5% calcium. Any lower, and interestingly enough higher, resulted in egg production and egg quality problems.

Chicken owners do not need to get qualifications in chicken nutrition to ensure that their flock gets a balanced feed. Commercially available laying feeds are readily available, or you can add oyster shell to your hen’s diet.

A note of caution about feeding additional calcium to chickens: it is ONLY laying hens that should get laying feed. Chicks and immature birds should get grower feed which has a far lower percentage of calcium. Feeding too much calcium to birds that don’t need it can result in growth deformities and other health issues.

Of course, chicken feeding isn’t only about calcium. Healthy chickens need a balanced diet that includes plenty of protein, calcium, vitamins, and minerals – they are omnivores who, if they are free-range, will enthusiastically tuck into just about anything they find on their walkabouts!

To keep chickens healthy and well fed, owners should provide a balanced staple feed and a selection of fresh fruits and vegetables. There are a few food no-nos like citrus and highly salted items, but in general, keeping a scraps bucket in the kitchen quickly becomes a treats bucket for the chicken coop!

Yolk color is often a hot topic among chicken owners. Quite simply, the more carotenoids a chicken consumes, the darker the egg yolk color will be. That’s a big word that just means that the more plants and natural foods a hen eats, the more orange the egg yolk will be. That is why free-range, or ‘farm eggs,’ have naturally darker yolks – they get to eat more vegetation, and it comes through in egg yolk color.

Providing ample water is, of course, essential to keep your girls healthy and happy. Not only when it is sweltering but also when temperatures are freezing. Be sure to check that water bowls are always in liquid form!


Chickens being given medications for diseases or infections can produce eggs that contain drug residues. If your chickens are being treated with drugs, it is advisable to check with your vet if an egg withholding period is required. Chicken dewormers are generally safe, and you can safely consume eggs from hens that have been routinely dewormed.


Poultry can be affected by internal or external parasites. While many can cause intense discomfort or illness, others can directly affect the quality of eggs that are produced. Internal parasites also affect how food is used within a chicken’s system. Your hens may be well fed but losing valuable nutrients to internal parasites.

Common Egg Quality Problems

Now that we have covered all the potential causes of any weird and wonderful eggs from your coop, it may feel a bit like a game of eeny-meeny-miny-moe to understand which issue is at play. While we cannot cover every possible egg quality problem, let’s go through some of the most common issues and identify the probable causes.

Chicken owners must remember that a holistic approach to chicken problems is always best. Even if you identify nutrition as a possible cause for odd-shaped eggs, also check that hens are not stressed, overheated, elderly, or sick.

Our little chicken friends may sometimes have a lot to say, but we don’t speak the same language, so aim for a multipronged approach when remedying egg quality issues.

ProblemCauseHow To Fix
Tiny eggsImmature hens that have not yet adjusted to the laying cycle. These mini-eggs rarely contain a yolk.Totally normal. You may need to graduate your pullets onto laying feed as they will soon begin producing eggs.small egg
Pale shell colorThe chicken breed is the greatest determining factor for shell egg color. Older hens, those with infectious bronchitis, or birds that are stressed may produce shells that are slightly lighter than usual. It can be an early sign of Egg drop syndrome – EDS ’76.  White shells are standard for many breeds. If eggs are paler than usual, check for signs of illness or stress.  pale eggs
Dirty eggsSticky  or watery stools or dirty laying nestsCheck the nutrition of the chickens and remedy any imbalances that may be causing loose poop. Ensuring laying box hygiene and collecting eggs promptly can also help.dirty eggs
Egg With No ShellMany possible reasons, but insufficient calcium is the most likely cause. It may also result from a defective shell gland or excessive salinity. (water that contains too much softener) It is also a symptom of EDS ’76 – also called egg drop syndrome.Correct the diet and provide a high calcium supplement like oyster shell. If it was a once-off, it might have been caused by a disturbance. Other dietary deficiencies like phosphorus can also cause this issue.egg without shell
Blood stained eggsBurst blood vessel while laying. It could also be caused by mites or issues related to obesity in caged birds.Young birds may present blood-stained shells, which is not serious. Overweight birds should be allowed to move around naturally, which will prevent prolapsed cloaca.bloody egg
Soft shelled eggsUnbalanced diet, shell gland infection, or hens nearing the end of lay. It may be a symptom of Egg drop syndrome – EDS ‘76Increase calcium-rich feeds and rule out possible infections. If hens are old, they may naturally be tapering off the laying cycle, and egg quality, specifically shell density issues, may be noticed.soft egg
Wrinkled EggsOvercrowding, defective shell gland, or infectious bronchitisEliminate all causes of stress and ensure that the bird has adequate space. If bronchitis is observed, quarantine and treat the affected bird.wrinkled egg
Cracked eggsHairline cracks in eggs can be caused by dietary deficiencies, heat stress, or salty water.Correct all possible causes. Note: discard any eggs that have cracks and are leaking as they may have been contaminated.
Rough sandpaper shellExcess calcium deposits on the surface of the shellToo much calcium or Vitamin D in the dietrough egg
Mis-shaped or elongated eggsYoung chickens at the start of the laying cycle, stress, crowding, or diseases like bronchitisTreat the cause of the condition. Pullets that are starting to lay may need time and slight diet adjustment to fix the issue.   Stress, crowding, and illness need to be addressed urgently to avoid the onset of additional health problems.
Corrugated EggsProblems during the internal ‘plumping’ process before the shell forms over the egg. More common in older hens or may indicate poor nutrition, stress, salty water, or mycotoxin-contaminated diets.Correct diet and eliminate all potential causes.
Runny whitesIt may indicate an illness in the hen but is more likely a result of the egg being stored for too long.Runny egg whites usually indicate that the egg has been stored for a long time. High temperatures also increase the rate at which the ordinarily thick, gloopy albumen becomes watery. Collect eggs as soon as possible after they are laid.

Does Storage Of Eggs Effect Quality?

If you detect problems with the quality of eggs produced by your flock, your hens may be totally innocent! Once an egg has been produced, any number of things can go wrong, which will ultimately affect the quality of the product you drop into your frying pan.

Six factors greatly affect the quality of eggs after they are laid:

  • Storage temperature – The temperature at which eggs are stored is one of the most significant post-laying factors affecting the quality of eggs. With higher temperatures, moisture is lost faster. Research has also indicated that carbon dioxide from the albumen escapes more rapidly.
  • Humidity – The lower the humidity, the faster the rate of moisture loss from an egg. This results in a loss of weight and deterioration of albumen quality.
  • Length of time it has been stored – Egg quality deteriorates the longer it is stored. They are highly perishable items. The length of time an egg can be stored depends on factors like the temperature and whether or not it has been washed.

Egg quality declines over time as the air pocket inside the becomes larger. At the same time, the white becomes runnier.

Top tip: If you need your eggs to last longer, store them with the pointy end pointing down. It will not save them indefinitely, but it will help keep them fresher for longer.

  • Whether the eggs have been washed – Store-bought eggs in the US have been washed. While this process removes any possible harmful contaminants that may have been on the outside of the shells, it also removes something called the bloom.

The ‘bloom’ is an invisible layer that occurs on the outside of eggs, which is applied during the last part of laying. It is a protective coating that prevents the egg from drying out and prevents bacteria from getting inside. Eggs which have had the bloom washed off should be refrigerated as they will spoil faster.

  • Hygiene conditions where the egg is laid and stored – Egg quality can be affected by contaminants like chicken feces on the outside of the egg. Owners need to make every effort to keep laying nests hygienic and provide clean nesting material, so eggs stay pristine from the moment they are laid.
  • Storage – If your eggs smell a little funky, it may not be because of anything your hens did! Egg shells are porous, so if you store them next to your jar of chopped garlic inside the refrigerator, you may end up with a hint of garlic flavor in your cookies and pancakes.

There are plenty of other strong odors like citrus and fish that eggshells can absorb. Although absorbing strong smells won’t affect the inherent quality of an egg, it will undoubtedly affect your enjoyment of it.

How Can You Tell If An Egg Is Bad?

Anyone who has had the misfortune of cracking a bad egg into a pan will be eager never to repeat the mistake! Chicken owners, particularly those with free-range flocks, frequently come across surprise egg stashes hidden around the yard, and deciding what to do with those eggs can be tricky. You don’t want to waste them, but carrying a sulfur stink bomb into your kitchen may not be something you want to try.

Besides simply inspecting stray eggs visually and sniffing them for any tell-tale signs of spoilage, the next step in determining quality is to do a float test. The older an egg is, the bigger the inside pocket of air will be. When you place eggs in a bowl of water, fresh eggs will sink and stay at the bottom while older ones may stand on end or float to the surface.

What Is Salmonella, And How Do You Get It From Eggs?

Anyone who keeps chickens to produce fresh eggs has probably had to field concerned inquiries about the risk of Salmonella. This bacterium is the main reason commercial eggs in the USA are washed before they land on supermarket shelves.

Salmonella can infect the inside or the outside of eggs. It is, however, invisible, so it will not affect the outward quality of an egg. Anyone who enjoys eating raw or minimally cooked eggs should only use pasteurized eggs.

According to the CDC, even healthy-looking chickens can carry salmonella germs. However, this does not mean you must get rid of your chickens. Maintaining good hygiene around chickens, frequent hand washing, and handling eggs safely will significantly mitigate any risks associated with possible Salmonella outbreaks in backyard poultry.

What Is A Lash Egg?

If you find a really unpleasant-looking, egg-like mass inside your chicken’s laying box, it may be a lash egg. We have not included lash eggs in our list of egg problems because it is not an egg at all, but it can be very disturbing to discover one in the coop.

It is typically a solid, rubbery, rather disgusting-looking build-up of tissue that is expelled in the same way as an egg. It may not be pleasant to see, but it results from your hen’s immune system trying to fight off an infection called salpingitis. You will need to consult a veterinarian to confirm the diagnosis and get the correct treatment.


Forrest Gump famously stated, ‘Life is like a box of chocolates; you never know what you’re going to get.’ For chicken owners, the same can be said about eggs! Owning your own flock of backyard chickens can be highly rewarding, but it can also open a whole new world of discoveries when it comes to variation in egg shapes, colors, sizes, and quality.

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