by Dr. Claire Peterson

Here at Frontier Veterinary Hospital, we are seeing more and more pet chickens as people are exploring how awesome it is to have fresh eggs straight from your own backyard! Unfortunately, I’m also seeing a lot of chickens coming in that either aren’t vaccinated or who have unknown vaccination status for Marek’s disease, and just wanted to send out a quick note on what Marek’s is and why we recommend purchasing ONLY vaccinated chicks.

What is Marek’s disease? Marek’s disease is a herpes virus in chickens that is really infectious and is ubiquitous (everywhere) in the environment already. There are several different forms (cutaneous, ocular, visceral, and neurologic), but the most well known is the neurologic form that slowly causes paralysis. Many sources talk about this disease in young chickens (2 to 5 months of age) but they can get the disease at any age. Not all chickens who get the virus get sick, but unfortunately there is no cure for the chickens who do get sick.

There is a vaccine against Marek’s disease, but it HAS to be done when the chick is still in the egg, or when it’s only 1 day old. After that, they’ll already be exposed to the virus, and then it will be too late. So the important thing for backyard chicken owners to do BEFORE you get any chicks, is to check who you are getting your chicks from and make sure they vaccinate. Chickens who are vaccinated for Marek’s will NOT give the disease to other chickens, especially given that the virus is already everywhere – even if you haven’t ever had chickens on your property before!

So do your homework beforehand and make sure you’ve got a good coop set up with protection from wild predators, a good source of commercial crumble or other feed, get your chickens from a vaccinated source, and enjoy those backyard eggs! If you’re looking for more information, Oregon State University has some great articles on their website here for small farms and backyard flocks –

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