hunthaven
Songster
In the last two months, I have lost four vaccinated hens to Marek's Disease--verified by my state lab. I have a fifth hen who I pulled from the coop today and placed in isolation for observation.
Since being overwhelmed by this onslaught of MD, I've done tons of reading and research, and I'm instituting some changes in my backyard flock. If you have experienced Marek's, you might want to consider doing the same.
I noticed that my four original birds, all vaccinated at the hatchery, have not exhibited symptoms of MD, but at least one of them is probably the source of my other cases. EVERY bird I have added to the flock since these four have all been vaccinated, and all but the last two have exhibited signs of Marek's, usually when they reach the point of lay.
SO--here's what I'm doing different.
1. No more deep litter system. After losing two birds, I debated cleaning out my deep litter coop and didn't do it because I reasoned that everything was already contaminated. After doing more research, I realized that my birds were shedding MD-infected dander every night in a small room, often with the windows closed against cold weather. My new and younger birds were being bombarded with the virus, which might have overcome their vaccination resistance. I am now cleaning my coop once a week (down to the bare boards, spraying with Odoban (which kills the virus), and refilling with a thin layer of Koop Clean. No more deep litter for us, not for a long time. AND no using the old litter for compost. If I spread the stuff in my yard, the wind will blow the virus everywhere. I put all the old litter into sealed trash cans and hauled it away.
2. No more introducing birds younger than six months to the adult flock. I have read that it takes a full six months for the Marek's vaccination to reach full strength. In the past, I have added birds to the regular flock as soon as they were big enough to fend for themselves, but from now on I will wait. I'll house the younger birds in a coop as far away from the adults as feasible.
"Vaccinate chicks - Administer MDV vaccine to chicks shortly after they hatch. It is given subcutaneously (under the skin) at the back of the neck. Chicks require 7 to 14 days in order to become immunized against MDV. Newly hatched chicks should not be put in the same environment as older flock members until they are at least 6 months old." See more at: http://www.poultrydvm.com/condition/mareks-disease:
3. I am vaccinating hatchlings and/day-old chicks TWICE: at one day old (myself or at the hatchery) and at 7 days old. I've learned to do it and yes, it's scary at first, but the disease is worse. Quote: "The information obtained in this study suggests that the productive infection with revaccinated MDV in chickens plays a crucial role in the induction of superior immunity. This finding may be exploited for the development of a novel MD vaccine that results in the persistence of the antigen supply and that maintains a high level of immunity and may also have implications for other viral oncogenic diseases in humans and animals." Source:https://cvi.asm.org/content/16/2/184
I know there's a lot of information about Marek's out there, and a lot of it is contradictory. I knew nothing when my first bird came down with it, and it's been heartbreaking to watch otherwise healthy birds break down in the throes of this disease. I hope this information can help you, and I hope they improve the vaccine so we can eradicate this disease.
Since being overwhelmed by this onslaught of MD, I've done tons of reading and research, and I'm instituting some changes in my backyard flock. If you have experienced Marek's, you might want to consider doing the same.
I noticed that my four original birds, all vaccinated at the hatchery, have not exhibited symptoms of MD, but at least one of them is probably the source of my other cases. EVERY bird I have added to the flock since these four have all been vaccinated, and all but the last two have exhibited signs of Marek's, usually when they reach the point of lay.
SO--here's what I'm doing different.
1. No more deep litter system. After losing two birds, I debated cleaning out my deep litter coop and didn't do it because I reasoned that everything was already contaminated. After doing more research, I realized that my birds were shedding MD-infected dander every night in a small room, often with the windows closed against cold weather. My new and younger birds were being bombarded with the virus, which might have overcome their vaccination resistance. I am now cleaning my coop once a week (down to the bare boards, spraying with Odoban (which kills the virus), and refilling with a thin layer of Koop Clean. No more deep litter for us, not for a long time. AND no using the old litter for compost. If I spread the stuff in my yard, the wind will blow the virus everywhere. I put all the old litter into sealed trash cans and hauled it away.
2. No more introducing birds younger than six months to the adult flock. I have read that it takes a full six months for the Marek's vaccination to reach full strength. In the past, I have added birds to the regular flock as soon as they were big enough to fend for themselves, but from now on I will wait. I'll house the younger birds in a coop as far away from the adults as feasible.
"Vaccinate chicks - Administer MDV vaccine to chicks shortly after they hatch. It is given subcutaneously (under the skin) at the back of the neck. Chicks require 7 to 14 days in order to become immunized against MDV. Newly hatched chicks should not be put in the same environment as older flock members until they are at least 6 months old." See more at: http://www.poultrydvm.com/condition/mareks-disease:
3. I am vaccinating hatchlings and/day-old chicks TWICE: at one day old (myself or at the hatchery) and at 7 days old. I've learned to do it and yes, it's scary at first, but the disease is worse. Quote: "The information obtained in this study suggests that the productive infection with revaccinated MDV in chickens plays a crucial role in the induction of superior immunity. This finding may be exploited for the development of a novel MD vaccine that results in the persistence of the antigen supply and that maintains a high level of immunity and may also have implications for other viral oncogenic diseases in humans and animals." Source:https://cvi.asm.org/content/16/2/184
I know there's a lot of information about Marek's out there, and a lot of it is contradictory. I knew nothing when my first bird came down with it, and it's been heartbreaking to watch otherwise healthy birds break down in the throes of this disease. I hope this information can help you, and I hope they improve the vaccine so we can eradicate this disease.
Sorry to hear of your losses 
