Disease Symptoms of Chickens

Updated November 21, 2016

Because chicken diseases can come on suddenly, it's important to note the symptoms so a sick chicken can be properly treated before the diseases worsens and spreads. Healthy chickens have bright, clear eyes; clean legs; and smooth, shiny feathers. According to the website on chicken diseases, a normal body temperature for chickens is 39.4 degrees Celsius.

Types of Chicken Diseases

Metabolic and nutritional diseases include fatty liver syndrome, rickets and cage layer fatigue. Infectious diseases are those caused by pathogens growing and multiplying in the body. Avian influenza, fowl pox, Newcastle disease and Marek's disease are examples of infectious diseases. Parasitic diseases are infestations with organisms and are usually contracted with an intermediate vector, although they might also occur from direct exposure. Lice, mites, parasitic worms and coccidiosis are common parasitic diseases.

Common Symptoms of Diseases

Fowl pox is a common virus that is usually spread by mosquitoes and shows symptoms such as retarded growth and reduced egg production. Newcastle disease, another highly contagious disease, has symptoms such as hoarse chirps, watery discharge, paralysis and facial swelling. Bronchitis has similar symptoms, along with eggshells that are rough. Symptoms for avian influenza include dehydration, facial swelling and respiratory distress. Marek's disease is an avian cancer with symptoms including weight loss, laboured breathing, grey eyes and diarrhoea.

Behavioural Diseases Symptoms

Unusual behavioural patterns can result in sickness or injury for the abnormally behaving bird, as well as its companions. One of the most dangerous behaviours is aggressive pecking. Other symptoms of illness might include a chicken that fails to move around, preening its feathers. Nervousness and not wanting to perch are also common symptoms of a behavioural disorder.

Tips and Considerations

Keeping accurate flock records helps in recognising a disease in its initial stages. Usually a slump in water and food consumption is the best indication there's a problem. Besides noting birds that appear unhealthy, caretakers should note and record actions. For example, hearing unusual sounds such as rattling or sneezing might indicate an illness.


It's important not to try to identify all types of poultry diseases. Because poultry farms require large monetary investments, heavy losses can be suffered from a wrong diagnoses if the wrong medication is given. Just a few diseases can be properly identified without the help of laboratory aids. Instead, a vet should be consulted when there's any doubt regarding a diagnosis.

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