An Overview of Marek’s Disease in Chickens thumbnail image

An Overview of Marek’s Disease in Chickens

Marek’s disease is one of the most common health issues chickens face. It’s a fast-spreading viral infection infected chickens that can occur in many different forms. As with all chicken diseases and illnesses, it’s important to know the clinical signs, symptoms, and prevention tactics for Marek’s disease.

To learn more and protect your flock, consult our overview of Marek’s disease in chickens.


Marek’s disease comes from a herpes virus called alphaherpesvirinae. Known as a chicken disease, it can also infect quail and, on rare occasions, turkeys. Marek’s is most common in younger chickens between three and 30 weeks old.

There are four forms of Marek’s disease, each affecting a different part of the body: the skin, the eyes, internal organs, and nerves. Each form also has its own different symptoms too. An infected chicken can display more than one form.


The Marek's disease virus spreads quickly, and it can survive for a long time in the right conditions. It spreads through dust and dander, making it easy for another bird to breathe it in and catch the infection.

This means that Marek’s disease can easily travel between affected birds and flocks on clothes or equipment. Unfortunately, infected birds with Marek’s disease remain carriers for the rest of their lives. Since no cure exists, it’s best to put down infected chickens to protect the rest of the flock.


Infected birds marek's disease will grow tumors on different parts of their bodies. The tumors most commonly affect the nerves on the legs, wings, and neck. These tumors eventually paralyze the birds.

An infected chicken might also develop tumors inside their body and on internal organs, causing a number of issues such as weight loss and difficulty breathing. A chicken infected with the skin form of Marek’s disease will have enlarged feather follicles that can lead to wounds and scabs.

The ocular form of Marek’s infects the eyes, leading to graying of the eye, a change in iris shape, and potential blindness.


There’s no cure for Marek’s disease, but there are several ways to protect your flock. First and foremost, you should provide newborn chicks with Marek's disease vaccine to prevent them from catching the disease.

Hygiene is another important habit for your flock. Keep your birds and their coop clean, especially when one of your birds has fallen ill. Consider utilizing poultry disinfectants, and be sure to keep the nesting pads, feeders, and chicken watering systems clean to prevent Marek’s disease and other illnesses from spreading.

As with most chicken matters, knowledge is power—and Stromberg’s is here to help. We hope this overview of Marek’s disease in chickens helps you prevent the infection or catch the issue early and protect the rest of your flock. With the right information and equipment, you can provide the safest and healthiest home for your chickens.