Another Mereks question

[silkie4]

I have been told that chickens over 8 months old will not get mareks...... Is this true? I have a 5 month old chicken that can't use her right leg. It just lags behind her. It hasn't improved in the last 4 days and I do have her isolated from the others. If this is Mereks, how long do they usually live?

 

[Michael Apple]

Here are some details about Merek's Disease:
http://www.merckmanuals.com/vet/poultry/neoplasms/mareks_disease_in_poultry.html
I have lost chickens in the past, mostly from local folks who raise chickens and don't take the precaution of vaccinating day old chicks. There are more than one strain of Marek's as you'll see in the information provided by Merck.