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What is Marek's Disease in Chickens?

Updated: Dec 29, 2023


What is Marek's Disease?

Have you ever heard of Marek's disease? If not, today is your lucky day! You'll learn all about the causes, if it’s treatable and how to sanitize your coop after Marek's strikes your flock. This way you won’t have an unnecessary panic attack like I did the first time I thought I had a chicken with Marek's!


What is Marek's Disease?

Sweet Georgia my Barnevelder


It was a few summers ago, and our daughter came running to the house telling me she thought Georgia (my precious Barnevelder) was dying. I ran out of the house and down to the coop to find Georgia lying on her back with her legs in the air. I have no idea why Marek’s was the first thing that entered my mind, but it was!


I got Georgia up off her back and brought her directly to the small kennel in our garage. After a few hours of observation, I realized Georgia was just fine! She was at the bottom of the pecking order at the time, and sadly, I think she was trying to play dead so the others would leave her alone. To this day, she’s a happy and healthy chicken and no longer at the bottom of the totem pole!


What is Marek’s Disease?

Marek’s disease is a highly contagious viral disease found in backyard and commercial chicken flocks. It is named after Jozsef Marek, a Hungarian veterinarian. Marek described the disease in 1907. It’s actually a chicken herpes virus that can wreak havoc on your flock. The good news is that humans can’t contract this highly infectious disease. Marek affects the chicken’s central nervous system and can cause paralysis. This is why I thought Georgia had it because she was stuck on her back. Marek’s can cause blindness and tumors on organs, muscles, and even the follicles of feathers. All in all, it’s a horrible virus.


What Are the Symptoms of Marek’s Disease?

Chickens may show signs of pale combs, weight loss, dehydration, diarrhea, depression, paralysis and loss of appetite. These symptoms can be found in other chicken diseases as well, so if you do have an ill chicken, don’t just assume it’s Marek’s, but be quick in separating the sick chicken away from the flock.


Is Marek’s Disease Treatable?

Unfortunately, Marek’s is not treatable and if your chickens catch this, it usually moves pretty quickly through the flock regardless of the vaccination status of the birds. Marek’s can be spread through chicken dust and dander, and we know there is never a shortage of that in a coop! Unfortunately, the virus can live dormant in chickens, but once the symptoms occur, it will likely be too late to save your chickens.


Is it Important to Clean My Coop After a Marek’s Outbreak?

Keeping a clean chicken coop is always important! But, if there is a disease outbreak, lice, mites, or other yucky things plaguing your coop, deep cleaning is of utmost importance! This is a great article on Marek’s disease and how to properly clean and disinfect your coop if you have been unfortunate to have this disease strike your flock. You basically need to deep clean and disinfect everything in your coop…even electrical outlets! It’s quite a process, but necessary to be able to keep chickens healthy. I clean our coop out 2-4 times a year. I’d rather stay on top of the coop hygiene to do our best to keep our flock healthy. I also give our chickens Strong Animals Chicken Essentials to fight off sickness and disease naturally by keeping their immune systems strong!


With knowledge comes power, and that is especially true when it comes to raising backyard chickens. By being aware of potential diseases like Marek’s, hopefully, you can stop them from spreading and keep your flock at its healthiest!


Until next time,


–The Wing Lady


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