Be careful with that link. Not everything is accurate. It lists wikipedia as one of it's sources and there is no guarantee that bad information is not placed on wikipedia by well meaning people. There is a lot of junk information floating around the internet regarding Marek's. First of all there is more than one way to vaccinate. Large hatcheries sometimes vaccinate while in the egg. Chicks can also be vaccinated using a small needle. Secondly, the virus in the vaccine is not the same as the Marek's virus. It is similar enough to cause immunity. Birds that are vaccinated and properly quarantined for a period of time after vaccination do not acquire the disease and do not shed the virus.
My sources for this are veterinarians in the poultry departments of universities and the veterinarian at the lab that makes the vaccine.
Also, there is more than one type of Marek's. The vaccine only protects against the paralysis type. You will probably never "see" a skin lesion on your bird. If you want to attempt to save your birds, put them in small cages with the food and water right in front of them. They may or may not go into remission (they are never cured - they just go into remission). It could take a few days, but will most likely be weeks. Birds that do not have this type of intensive care only have a 5% survival rate. My neighbor and I have both saved birds this way. The recovery is long, but Mareks is not painful. The pain and suffering happens when the bird is not confined and is injured by other birds or hurts itself trying to get around. If the paralysis gets to the neck, you probably will not be able to save it because it won't be able to eat or drink. At that point the humane thing might be to put it down. Whether or not you want to save the birds or cull them is your decision. All of your birds have been exposed and are carriers for life. If you are not selling or showing birds, that may not be a problem. All unvaccinated birds are potential carriers. Marek's is everywhere in the environment and is worldwide. That is why more and more people are choosing to vaccinate. We were hit with Marek's once, and now all new birds on my place will have been vaccinated as chicks.
Good luck
