Chicken disease symptoms: The vet’s guide to what you need to know

Pet chickens are inexpensive and require minimal care; that is why backyard chicken coops rose in popularity over the past few years. Not only do they produce healthier eggs, but free-range chicken is also tastier than the ones you buy in the supermarket.

But just like any other animal, there are diseases in chickens you should watch out for. Any changes in their skin color, behavior, and secretions mean something. Let this article guide you on what are the chicken disease symptoms, their causes, and how to prevent them.


How do you know if your chickens are sick?

You have to watch out for general signs of sicknesses in chickens and gather further data if there’s an underlying disease. Here are the signs you should look for in order to know if your chicken is sick.


Weak or inactive chickens

Happy and healthy chickens move a lot during the day. If you observe chickens that prefer to sit and hide in the chicken coop for most of the day, there must be something wrong. Sick chickens are usually weak or inactive because they try to conserve their energy and keep warm.


Poor appetite

Chickens are like humans too, they eat more if they like the food, and they eat less if they are sick. If you’re feeding the chickens and you spot a chicken with poor appetite, try to provide other foods they might like—for example, corn, cooked oatmeal, or mealworms.

If you tried giving their favorite foods and still exhibit a poor appetite, this indicates a sickness.


Changes in behaviour or actions

If your chicken acts or behaves differently than what they used to, this is a sign of a problem. Examples are; holding their wings in a weird position, limping, trouble standing up, an unusual smell, staying away from the rest of the flock, or any odd body language.


Observe for stomach problems

A dark and food-like vomit of chickens may indicate a tumor, impaction, dead section of the intestines, or blocked passage. If chickens throw up yeast-like and sour-smelling liquid, this may indicate peritonitis (inflammation of the abdominal wall due to the fungal or bacterial infection).

If chickens vomit clear fluids, this is a sign of ascites (fluid build-up in the abdomen).

Also, observe the faeces: Their texture, changes in smell, and unusual colour. All of these indicate stomach problems in chickens and needs immediate care.


Observe their eyes

Watch out for runny or cloudy chicken eyes that may indicate that they are under the weather. If you also observe that one or both eyes are closed most of the time instead of being usually alert, investigate further.


Observe for changes in the comb, wattle, or skin colour

Observe any swelling, lesions, or colour changes in the different body parts of the chicken. Any changes are likely a sign of sickness, and it is best to gather further information.


Check out the egg quality and production

When a chicken suffers from an illness, the egg quality and production are most likely to suffer. Check the egg quality if the shell is too soft, or the egg yolk is too watery, weird shaped eggs. Also, observe changes in the production of the eggs.

If the chicken suddenly is unable to produce an egg, the egg production lessens, or you notice a difficulty in laying eggs, this may be a sign of sickness. [ 1 ]


Chickens are losing feathers


The most common reason chickens are losing feathers is due to their annual moulting. The natural shedding of the hen’s or roosters feathers happens once a year in preparation for the winter. The decreased light during the fall season triggers this moulting process.

The moulting process takes about 4-12 weeks, depending on the chicken’s breed. It requires the chicken to use tremendous amounts of energy to grow new and healthy feathers. This is not of the chicken disease symptoms you should be afraid of, especially when the feather falls off before winter.

However, it is best to observe your chickens closely during the moulting season. Observe for any signs of illness or weakness so the chickens will survive and come out strong. Make sure that the chickens avoid stress factors during the moulting season. The chicken coop must be well-sanitized; they must be safe from predators, avoid fighting with other chickens and be fed a high-protein diet.

Also, avoid handling or touching the chicken because they are highly sensitive during this season. [ 2 ]


Amino acid deficiency

The most common reason why chickens’ feathers are unable to develop properly is because of amino acid deficiency. Inadequate levels of methionine (the essential amino acid requirement in chickens) result in poor feathering and delayed growth of the chicken.



If the feathers are broken off or pulled off, especially in the heads of the hens or its back, it can be a sign of mating. Roosters, on the other hand, may have missing feathers on their breast area.

This is not something owners should worry about because it will grow back after the breeding season.



If there are no feathers on the vent or abdominal area, this may indicate the presence of an external parasite like poultry lice or fowl mite.


Chickens With Swollen or Scally Feet or Beak

Scaly feet disease in chickens

The infestation of the knemidocoptes mites causes the scaly legs of chickens. These mites hide and grow in the legs, feet, wattles, or beaks of the chicken. The “scaly feet” disease is highly contagious and spreads to other chickens quickly.

The mites will cause an overproduction in the skin cells resulting in flakey and irritated skin. For chickens whose beaks got affected, this may result in the permanent deformity of their beak.

These mites live on the floor or ground of the chicken coop, especially in damp conditions. Not only is chicken affected by the scaly feet disease, but any type of bird of any age as well. If the disease is left untreated, the infection may further worsen and lead to their death.


How do you treat the scaly feet disease in chickens?

The key to treating the chicken’s scaly feet is patience and constant treatment. It will require a couple of weeks to make sure the crusts and scales fall off, and everything returns to normal. There are topical sprays or ointments made of active ingredients to kill the mites present. It also has natural oils to provide moisture and prevention of further infestation.

Other people use petroleum jelly for repeated application on the scales. Petroleum jelly will soften the scales and crusts and will suffocate the mites.


Bumblefoot or Swollen foot of chickens

Bumblefoot, otherwise known as plantar pododermatitis, is a condition where the chicken’s foot becomes swollen. You will notice this when the chicken starts to limp or cannot stand on the swollen foot.

Other chicken illnesses symptoms of the bumblefoot are lameness, heat, and black scabs. If the swollen foot is left untreated, the condition may become chronic, and the chicken may die. Bumblefoot starts with a foot injury or a cut, and the staphylococcus bacteria enter the chicken’s foot.

There will be abscess formation and swell filled with fluid.


How do you treat the swollen foot in chickens?

When handling a chicken with bumblefoot, always wear gloves because the staphylococcus infection is contagious. The first step is to immediately separate the infected bird and place it in a cage with soft litters (e.g., pine shavings).

Take a pain of very warm water with a cup of Epsom salt. Let the chicken soak its feet on the pan for 15 minutes, but make sure the chicken doesn’t drink it.

After soaking, carefully pull off the scab; if it doesn’t come off immediately, try soaking its feet again. If the scab comes off, there will be an open wound on the chicken’s feet. Rinse it with hydrogen peroxide, apply topical antibiotics, and cover it with sterile gauze. Change the wound dressings daily until the wound heals.

In addition to a wound dressing, oral antibiotics will help treat your chicken’s bacterial infection. Poultry stores or veterinarians can help you with this. Make sure to follow the dosage instructions of the oral antibiotics.


How do you prevent the swollen foot in chickens?

The best way to prevent Swollen foot and other chicken diseases is a clean chicken coop. Always maintain cleanliness, and make sure the place is dry. Remove sharp objects or wires that may cause an open wound to the chicken.


Chickens skin changes colour: Pale, pink, purple, or black

Pale chicken skin

If a chicken’s skin is pale, it is a sign of anaemia caused by excessive mite infestation or Chicken Anemia Virus (CAV). Excessive mites such as the infestation of the knemidocoptes mites may lead to anemia wherein the mites survive by sucking the chicken’s blood.

A lot of blood will be lost, and as a result, the chicken’s skin, comb, or wattle become pale.

The Chicken Anemia Virus (CAV) is another reason for the chicken to have pale skin. CAV is the cause of Infections, Chicken Anemia, Blue Wing Disease, and Chicken Anemia Agent. It is a vertically transmitted viral infection, meaning the mother hen gave the condition to its chicks.

Chickens with CAV lose their bone marrow density, become pale, anaemic, and have low immune systems.

CAV symptoms other than pale skin and other parts are weakness, anorexia, and cyanosis (bluish discolouration). The chicken may appear tired all the time and does not move around a lot. The severely sick chickens die within two to four weeks, while survivors usually have stunted growth.

Fortunately, CAV is uncommon these days thanks to available vaccinations for chicken. [ 3 ]


Purple chicken skin

If the chicken has purple skin, it only means one thing; it doesn’t get enough oxygen. The chicken turns bluish to purple due to low oxygen levels in the blood called cyanosis or the blue disease. Pneumonia and fowl cholera (a bacterial disease) are diseases that lower the body’s oxygen levels.

The fowl cholera may lead to cold stress that allows the bacteria to multiply rapidly. The chicken may die within 6-18 hours after acquiring the infection. Since the disease is bacterial in nature, the immediate intake of oral antibiotics is the recommended treatment.

Ensure that the chicken coop does not have a cold temperature, or incubate the chicken if needed. Like CAV, fowl cholera has widely available vaccinations.


Black chicken skin

Black chicken skin for some breeds is normal. Black scabies is not normal, but black skin is expected for the Silkie breed and Ayam Cemani. The Silkie has beautiful but unusual features. They have plumage and satin-like feathers, black skin, black bones, blue earlobes, and five toes on each of its feet (the normal is four as you can recall).

The breed from Indonesia called Ayam Cemani is all black. It has a dominant gene that produces hyperpigmentation, otherwise called fibromatosis. This causes the all-black feature of the Ayam Cenami breed (black skin, feathers, beak, internal organs, and bones). [ 4 ]


What causes eye problems in chickens?

Several eye disorders affect chickens; this may come from eye infection (caused by bacteria, virus, or fungus) or eye injury (due to blunt trauma).


Pink Eye

One of the common eye disorders of chicken is “pink eye” or conjunctivitis (inflammation of the inner eyelid). Like in humans, Pink Eye is caused by bacteria. It can also be a result of trauma and exposure to irritants like parasites and other foreign bodies for chickens.

Systemic illnesses, respiratory infections, and other disorders can also lead to pink eye development.



Cataracts in chickens appear as a clouding of one or both of the eye’s natural lens. If a chicken has a cataract, light cannot get through, resulting in the chicken getting blind.

There are five causes of cataracts in chicken: genes, avian encephalomyelitis or Marek’s disease, poor diet, and environmental factors. Avian encephalomyelitis (AE) and Marek’s disease are viral infections that reach the eyes’ retina and cause cataracts.

If the chicken lacks omega-three fatty acids and anti-oxidants on its diet, it may lead to cataracts as well. As for the environmental factors that lead to cataract, the exposure to ammonia, and continuous lighting contributes to the eye disorder.


How to prevent eye disorders in chickens?

Here are some tips on how to prevent eye disorders in chickens:

  • Provide a safe environment for the sick chicken, and separate it from the flock
  • The environment must be safe from sharp edges, free of dirt, warm, comfortable, and easy access to food and water
  • Clean the chicken coop regularly to avoid the accumulation of dust particles (foreign bodies may enter the eyes of the chicken)
  • Limit the stress factors of the chicken (e.g., predators, cold, limited space to roam, and weather problems)
  • Have the chickens been vaccinated from viral or bacterial infections?
  • Make sure to provide enough food and water to the chicken. The diet must be high in protein, omega-3, and antioxidants.
  • Veterinarians usually prescribe ophthalmic ointments or antibiotic drops to prevent further infection.


Changes in the dropping: Mucus, diarrhea or blood

Coccidiosis is the main culprit

The number one killer of brooder chickens is the disease called coccidiosis. It is an intestinal disease caused by a parasite that lives in the intestines of the chicken. This results in damage to the intestinal tract and poor absorption of nutrients and minerals of the chicken.

The most common clinical manifestation of the disease is the presence of blood or mucus on the chicken’s manure. The symptoms may appear gradually and even disappear suddenly. This means that the chicken appears fine one day and becomes very ill or unexpectedly dies.

If you want to go really to in-depth you should check out my article on coccidiosis in chickens here…

Other symptoms of coccidiosis are diarrhoea, weakness, pale skin, poor appetite, ruffled feathers, poor growth, weight loss, or insufficient egg production. Not all symptoms appear altogether, so if you suspect coccidiosis, consult a veterinarian to confirm the diagnosis.


Treatment of Coccidiosis

The recommended treatment is by adding Amprolium to the water of the chicken. Amprolium will block the growth and production of the parasite in the chicken’s intestine. If the chicken does not eat or drink properly, it is best to give the medication orally.


Prevention of Coccidiosis

Some chicken owners administer Amprolium to their chicken to prevent the development of Coccidiosis. It is best to consult a veterinarian before giving the medication.


Bad or fewer eggs from otherwise healthy chickens

Healthy chickens lay an egg every 24 to 46, under normal and ideal conditions. If your chickens stop laying eggs or decreased their production, there must be an underlying problem.

This may be due to stress, moulting process, ageing, or insufficient light. There are steps you can take to fix this problem, while there are factors you just can’t change. Here are some tips you should remember if you notice bad or fewer eggs from your chicken.


Confirm the egg’s location

It’s hard to assume that your chicken doesn’t lay an egg if they start hiding their eggs elsewhere. Or try to figure out if there are egg thieves.



If there are no confirmed egg thieves or no hiding places of the eggs, consider the daylight exposure of the eggs. The most common cause of inadequate egg production is the lack of exposure of the hens to daylight. The hen needs at least sixteen hours of daylight exposure to produce the desired eggs.

If this is not met, they may stop laying eggs due to hormonal changes. For days that have shorter daylight, consider supplemental lighting.


Stress factors

The stress of chickens may be caused by predators, dirty environment, overcrowding, loud noises, aggressive hens, poor nutrition, illness, and bad environmental conditions. Make sure to avoid these at all costs to ensure a healthy environment for the chicken.

Allot 5-10 square feet of outdoor space per bird so they won’t feel overcrowded. Provide one dry bedding and nesting box for every four hens so they can lay their eggs properly.



Ideally, hens need 38 different types of nutrients to perform their best when it comes to laying eggs. Deficient supplementation is as bad as over-supplementation, so this is something chicken owners should remember. For optimal laying of eggs, a hen must consume four grams of calcium daily.



As mentioned earlier, the moulting process is when chickens grow new feathers in preparation for the winter season. In this stage, the hens are expected to stop egg production, and this is normal.

The moulting process lasts up to 16 weeks, and once it is over and the chicken has new feathers, the egg production will resume.


Sudden death in otherwise healthy chickens

Heart attack

For healthy chickens that undergo sudden death, the most common cause is a heart attack. This is common among fast-growing broiler chickens. The heart attack starts with a wing-beating, short and terminal convulsion, and the chicken flips on its back. A heart attack is often caused by different stress factors.



This sudden death of the chicken is caused by a fully-formed egg getting stuck and is unable to come out. The egg may be too big, or the presence of injury to the hen’s reproductive gland, or calcium deficiency. Young and overweight hens are prone to the egg-bound indictment.

Of course, another reason for the chicken’s sudden death is an accident. Just make sure not to leave around sharp edges or anything that may cause injury to the chicken.

Lastly, your chicken may die of old age. I know this sounds like a precedent moment, but if you have dozens of chickens in your coop, will you remember all of their ages? I don’t think so. The average lifespan of chickens is 5-10 years, and unless you track and monitor the age of all your chickens, death may come suddenly.


Final thoughts

Now that you’re aware of the chicken disease symptoms, you can confidently take care of your chickens at home. Always try to make it a habit to observe your chicken’s actions while feeding them.

Please take note of any unusual movement or changes in their appearance. As much as possible, please do not waste any time, assess further, and seek help for their treatment. Chickens are like humans that need tender loving care to thrive.