Do chickens showing symptoms of Marek's ever survive? And vaccination question

Marek’s is a nasty disease. Once a flock is infected, it is always infected and all chickens in that flock are carriers for life. It can survive in the ground for a long time even without chickens present.

When Marek’s infects a flock, not all chickens always develop the tumors that cause the problems. If you have a small flock the percentages don’t really mean much, but in a larger flock it’s not unusual for more than half to never show any symptoms.

Different strains of Marek’s seem to concentrate on certain areas. Here Marek’s typically affects the legs and wings. In other parts of the country that might be internal organs or the neck. That does not mean it only affects those areas, just that it tends to attack those areas more than others. Sometimes the tumors will kill directly, sometimes it makes the chicken immobile so it can’t eat or drink so it dies of thirst or starvation. Some can survive an attack but a lot don’t.

The only Marek’s vaccine in the US I’m familiar with is that turkey virus, though I have read about something different going on in the UK. That does not mean I know that other vaccine is not in the US, just that I have not heard of anyone specifically using it. Maybe a vet can give you accurate information on that. I also do not know if that other vaccine makes them a carrier or not. Maybe another question for a medical professional with knowledge of those vaccines.

The turkey vaccine does not prevent them from getting Marek’s. It is possible they can still be infected with chicken Marek’s and be carriers. What the Turkey vaccine does is prevent the tumors that cause the problem from developing. If you know you have Marek’s in your flock you should get them vaccinated before they are exposed to the flock. Since Marek’s floats on air you need to go to length’s to keep them separated until the vaccine takes effect.

A chicken vaccinated with Turkey Marek’s will not become a carrier because of that vaccination. I see no reason to not show that chicken just because it has been vaccinated with Turkey Marek’s. However, if you know that you have chicken Marek’s in your flock, I would consider it unethical to show that chicken and spread the disease even if it has been vaccinated with Turkey Marek’s and does not show symptoms itself. If you have Marek’s in your flock, it is a carrier.