Marek's disease vaccines
Marek's disease is a herpesvirus disease of chickens that causes paralysis, tumours and immune suppression. The virus spreads in feather dust and survives for months in sheds, so almost every flock is exposed. It cannot be treated; protection comes from vaccinating chicks at the hatchery on day one (or in ovo) with HVT, Rispens (CVI 988) or bivalent vaccines.
Signs to watch for
- Paralysis of legs or wings — classic 'one leg forward, one leg back' posture
- Grey, irregular pupil ('grey eye') and blindness
- Weight loss and pale birds
- Tumours in liver, spleen, kidneys, nerves or skin
- Increased mortality from about 6 weeks onwards
Which birds are at risk?
Chickens of all types; signs usually appear from 6 weeks to several months of age. Long-living layers and breeders are most at risk.
How vaccination protects your flock
Marek's vaccines are given once, at the hatchery, by injection to day-old chicks or in ovo. Cell-associated vaccines are stored in liquid nitrogen and must be thawed and mixed exactly as instructed. Good brooding hygiene is important because chicks need about a week after vaccination to build immunity.
Marek's Disease vaccines from Shiv Sales
Administered at the hatchery for day-old protection against the immunosuppression and tumours caused by Marek's disease virus.
Marek's Disease: common questions
At what age is Marek's vaccine given?
On the first day of life at the hatchery (subcutaneous injection) or in the egg (in ovo) before hatch. It is not given later on the farm.
What is the difference between HVT and Rispens vaccines?
HVT is a turkey herpesvirus that protects against Marek's; Rispens (CVI 988) is an attenuated Marek's strain that gives stronger protection against very virulent strains. Bivalent vaccines combine both for layers and breeders.
Can Marek's disease be cured?
No. There is no treatment. Affected birds should be culled, and future flocks protected by correct hatchery vaccination and hygiene.
Related guide
Why vaccines fail — and how to prevent it
When a vaccinated flock gets sick, the vaccine itself is rarely the problem. Most failures come from what happens between the fridge and the bird.
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Signs, affected ages and vaccines for the 12 most important poultry diseases.
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This page is general information for farmers and does not replace veterinary advice. Always follow the vaccine manufacturer's instructions.
Need help choosing the right vaccines?
Talk to our team for a vaccination schedule built around your flock, location and disease pressure. Consultation is free for customers.