Marek's Vaccination in Unexposed Chicks Over a Day-old

[LikeTurkeys]

Hello all,
About a year ago my flock was exposed to a very mild strain of Marek's disease. Out of 60 young chickens, 1 bird developed paralysis and was euthanized, and 2 developed mild ocular deformities.

Since then I have maintained a flock closed to adult birds and only brought in day-old chicks who are vaccinated for the disease. All of the chicks that we hatch are vaccinated as soon as the hatch is complete.

So far so good. We haven't had any more symptoms of the disease. Our chickens are doing very well and we have been hatching (and vaccinating) a lot of chicks this year. But since there are 1000 doses and we recently invested in a vaccination gun, I decided I would advertise vaccination to other chicken owners who would like to get their chicks vaccinated.

All information online indicates that ONLY day-old chicks should be vaccinated, or even in-ovo at 18-19 days of incubation. This is what we have been doing. But my understanding is that this is because the chicks could be potentially exposed to Marek's disease in the environment. What if you have a clean flock? Let's say that a new chicken keeper just bought a few unvaccinated day-old chicks at the local feed store. The chicks should be free from Marek's disease at that point. He brings them home, and after owning them for a few weeks, realizes that it would be advantageous to have them vaccinated for Marek's disease. Given that the chicks have never been exposed to the virus, the effectiveness of the vaccine should be the same as if they were vaccinated at a day old.

I have been unable to find studies showing the effectiveness of Marek's disease vaccination in specific pathogen-free birds who are greater than one day of age. I would like to offer vaccination services to those with older birds, but hesitate to contradict all the information I have read online.

I would love some thoughts on this. Thanks.

 

[MottsHomestead]

This could work, however simply bringing the birds to your property to be vaccinated could expose them to the virus. Making it pointless. You want the birds to have no contact with the virus before the vaccine, and for a few days after to build up immunity. This is why it is best done on day old chicks, as they haven’t had any time to be exposed.

 

[McChooky]

Its my understanding starting with a vaccinated flock eliminates the need to vaccinate your own chicks .They must be vaccinated at one day old if they're being added to a vaccinated flock. A vaccinated broody hatching fertile eggs is basically vaccinating the chicks at one day old.

 

[LikeTurkeys]

This could work, however simply bringing the birds to your property to be vaccinated could expose them to the virus. Making it pointless. You want the birds to have no contact with the virus before the vaccine, and for a few days after to build up immunity. This is why it is best done on day old chicks, as they haven’t had any time to be exposed.

I considered this, doing it off property is a possibility.

Its my understanding starting with a vaccinated flock eliminates the need to vaccinate your own chicks .They must be vaccinated at one day old if they're being added to a vaccinated flock. A vaccinated broody hatching fertile eggs is basically vaccinating the chicks at one day old.

Unfortunately, this is not the case. Vaccinated chickens won't automatically vaccinate others. Every chick has to be vaccinated for it to work. I've also stopped hatching under broodies because it's impossible to prevent exposure that way if the hen is shedding the virus. It makes it a hassle for small hatches because it becomes expensive real fast.

 

[McChooky]

I considered this, doing it off property is a possibility.

Unfortunately, this is not the case. Vaccinated chickens won't automatically vaccinate others. Every chick has to be vaccinated for it to work. I've also stopped hatching under broodies because it's impossible to prevent exposure that way if the hen is shedding the virus. It makes it a hassle for small hatches because it becomes expensive real fast.

Why vaccinate chicks from a vaccinated flock? They're exposed to it from day one.

 

[Sussex19]

Unfortunately, this is not the case. Vaccinated chickens won't automatically vaccinate others. Every chick has to be vaccinated for it to work. I've also stopped hatching under broodies because it's impossible to prevent exposure that way if the hen is shedding the virus. It makes it a hassle for small hatches because it becomes expensive real fast.

I agree with this, and you would have to be very careful that they didn't get exposed to it beforehand and I think for a couple of weeks after.

 

[LikeTurkeys]

Why vaccinate chicks from a vaccinated flock? They're exposed to it from day one.

Not necessarily. If the flock is vaccinated but not infected, they will not be shedding the virus. Thus chicks will also have to be vaccinated in order to gain immunity. If the flock is vaccinated and infected, they will be actively shedding the virus in small amounts but not showing symptoms.

You don't want unvaccinated chickens to be infected by virus shed by infected vaccinated chickens. Rather, you want to induce immunity by vaccinating them with a look-alike virus (like a turkey herpes virus) that will not actually produce symptoms or spread from chicken to chicken. Precautions have to be taken to prevent exposure - like sanitizing eggs and hatching them in an incubator, as well as keeping the chicks separate for 14 days.

 

[McChooky]

. Birds must get the vaccine before they are exposed to the virus. Then the birds need about 4-7 days for the vaccine to do its work.https://extension.psu.edu/mareks-disease-in-chickens

 

[McChooky]

Not necessarily. If the flock is vaccinated but not infected, they will not be shedding the virus. Thus chicks will also have to be vaccinated in order to gain immunity. If the flock is vaccinated and infected, they will be actively shedding the virus in small amounts but not showing symptoms.

You don't want unvaccinated chickens to be infected by virus shed by infected vaccinated chickens. Rather, you want to induce immunity by vaccinating them with a look-alike virus (like a turkey herpes virus) that will not actually produce symptoms or spread from chicken to chicken. Precautions have to be taken to prevent exposure - like sanitizing eggs and hatching them in an incubator, as well as keeping the chicks separate for 14 days.

Hello all,
About a year ago my flock was exposed to a very mild strain of Marek's disease. Out of 60 young chickens, 1 bird developed paralysis and was euthanized, and 2 developed mild ocular deformities.

Since then I have maintained a flock closed to adult birds and only brought in day-old chicks who are vaccinated for the disease. All of the chicks that we hatch are vaccinated as soon as the hatch is complete.

So far so good. We haven't had any more symptoms of the disease. Our chickens are doing very well and we have been hatching (and vaccinating) a lot of chicks this year. But since there are 1000 doses and we recently invested in a vaccination gun, I decided I would advertise vaccination to other chicken owners who would like to get their chicks vaccinated.

All information online indicates that ONLY day-old chicks should be vaccinated, or even in-ovo at 18-19 days of incubation. This is what we have been doing. But my understanding is that this is because the chicks could be potentially exposed to Marek's disease in the environment. What if you have a clean flock? Let's say that a new chicken keeper just bought a few unvaccinated day-old chicks at the local feed store. The chicks should be free from Marek's disease at that point. He brings them home, and after owning them for a few weeks, realizes that it would be advantageous to have them vaccinated for Marek's disease. Given that the chicks have never been exposed to the virus, the effectiveness of the vaccine should be the same as if they were vaccinated at a day old.

I have been unable to find studies showing the effectiveness of Marek's disease vaccination in specific pathogen-free birds who are greater than one day of age. I would like to offer vaccination services to those with older birds, but hesitate to contradict all the information I have read online.

I would love some thoughts on this. Thanks.

You still have to isolate them for a minimum of 4-7 days after they get the vaccine off your property because the dander is everywhere.You would also have to isolate chicks you bought that were vaccinated if your flocks vaccinated.Simply removing the chicks and vaccinating them and adding them back to the flock makes the vaccinations useless is what I've read.You may as well not vaccinate them if you don't isolate them a week.

 

[Sussex19]

You still have to isolate them for a minimum of 4-7 days after they get the vaccine off your property because the dander is everywhere.You would also have to isolate chicks you bought that were vaccinated if your flocks vaccinated.Simply removing the chicks and vaccinating them and adding them back to the flock makes the vaccinations useless is what I've read.You may as well not vaccinate them if you don't isolate them a week.

Precautions have to be taken to prevent exposure - like sanitizing eggs and hatching them in an incubator, as well as keeping the chicks separate for 14 days.

It sounds like they are doing this.