Most Chicken Neurological Diseases are Preventable

From Aspergillosis to Wry Neck: Chicken neurological diseases and how to prevent them.

Most Chicken Neurological Diseases are Preventable

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You can prevent and control most chicken neurological diseases with nutrition and hygiene.

Diseases are an unfortunate reality when it comes to lifeforms, and poultry is no exception. Most of the multiple diseases that affect a chicken’s nervous system have the same clinical signs. Common signs are full or partial paralysis of one or multiple body parts, loss of balance, walking in circles, blindness, wry neck, and even convulsions. 

Thankfully, there are a few practices that can decrease the likelihood of one of these chicken neurological diseases occurring. We’ll touch on the most common neurological diseases seen in poultry and actions that can help prevent them. General prevention includes excellent biosecurity, buying from NPIP tested flocks, and rigid quarantine of new or sick birds. While frightening to encounter, we can prevent most neurological diseases through diet, environmental control, and disease-specific vaccines. 

Aspergillosis: This is a pulmonary disease found in young poultry that directly results from mold spore inhalation. All the signs of respiratory infection are present, and the common neurological symptoms are wryneck and tremors. The mold spores are usually found in contaminated bedding or improperly sanitized incubating and hatching equipment. You can do prevention through thorough cleaning of equipment and frequent litter changes as the chicks soil it. 

Botulism: The notorious Clostridium botulinum bacterium can infect many species, and poultry is no different. It is neurotoxic and eventually blocks the cells in the body from receiving signals. Paralysis begins in the legs, wings, and neck. Outbreaks occur most commonly in waterfowl. This toxin is produced by plant and animal waste in the form of rotting vegetation and carcasses. Prevent botulism by removing any dead birds, controlling flying insects that may serve as a vector, reducing standing water, and not feeding any rotten or questionable table scraps to poultry. 

Eastern Equine Encephalitis: Most commonly infects horses. However, EEE has been known to cause central nervous system infections in poultry. Signs include loss of balance, leg paralysis, and tremors. This is commonly attributed to mosquitos carrying the disease from wild birds. Controlling mosquitos, clearing standing water, and using wild bird netting can prevent EEE. 

Encephalomalacia: This disease is the result of vitamin E deficiency within a flock. Signs are problems balancing, tremors, and paralysis. Lack of vitamin E causes softening of the brain tissues, which will lead to typical neurological symptoms. Preventative measures include feeding balanced diets and ensuring birds have the correct amounts of vitamins and minerals for their age. Selenium is a beneficial vitamin to add to the diet because it helps with the metabolism of vitamin E, but too much can cause toxicity. 

Encephalomyelitis: Marked by the loss of balance coupled with tremors and paralysis, Encephalomyelitis is a nasty neurological disease that results from lesions growing on the bird’s brain and spinal column. Vaccinate birds against this viral disease ideally before the bird begins to lay. This disease can also occur in birds that eat a high-saturated-fat diet, so keep treats to a minimum for prevention. 

Marek’s Disease: Well known and very common, Marek’s is a viral disease that results in the enlargement of peripheral nerves. Neurological signs include weakness and paralysis, but the bird may also grow tumors throughout various organs. Once Marek’s is seen in a flock, it is highly contagious and life-threatening. The vaccine for Marek’s is effective, it is given shortly before or after the bird hatches, and most hatcheries and breeders offer it for a small fee. 

Mycotoxicosis: This collection of ailments comes from the ingestion of toxic fungi in the form of moldy feed. Poor feed quality or bad storage techniques are the usual suspects here. Symptoms again are poor coordination and paralysis, but birds can also develop lesions in and around their mouths. Often with this type of disease, signs are subclinical and result in a chronic, unseen weakness that increases the bird’s susceptibility to other illnesses. Prevention includes buying feed from trusted sources and inspecting feed for apparent signs of mold. 


Newcastle Disease: A viral disease that was recently in the news, signs include tremors, wing and leg paralysis, convulsions, neck twisting, and walking in circles. The other symptoms mirror those of a respiratory infection, though they’re not always present. This zoonotic disease can transmit to people. There is an effective vaccine available for Newcastle Disease. 

Nutritional Myopathy: Myopathy means “muscle disease” and is due to inadequate nutrition. The muscles break down and stop working as intended, leading to coordination and balancing issues. This results from a lack of Vitamin E, methionine, and cysteine, the latter two being amino acids mandatory for healthy growth. Providing nutritious feed is the best prevention. 

Polyneuritis: A result of thiamine deficiency. Thiamine is a key player in the glucose metabolism taking place so that the brain can receive the energy needed to function. The first signs of this deficiency are the bird sitting back on its hocks and “star gazing” with its head rolled back over its shoulders. The bird will eventually become paralyzed and lose interest in eating. This is another disease where good quality feed is the prevention.  

Whether through providing the right vitamins, vaccinations, or a mold-free coop, it can be easy to prevent chicken neurological diseases.

Originally published in the 2021 special issue of Backyard Poultry — A Natural and Sustainable Flock — and regularly vetted for accuracy. 

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