Did all your previous birds die when you had Marek's diagnosed. If not, then some of the remaining birds will be carrying the virus. The thing with Marek's is that they can be infected and then it lies dormant until something triggers an outbreak, usually a stress of some sort. My gut feeling is that this bird is exhibiting Marek's, but is not suffering the fatal tumours that kill. The vaccine is supposed to prevent that, so maybe it is doing it's job.
From my experience with Marek's, birds that have been found fallen and stuck in unusual places have had an attack of it. Some die pretty quickly afterwards and it is clearly not as a result of the fall. Others battle it and some recover.... but then I have one of the milder strains of the virus.
From my experience with Marek's, birds that have been found fallen and stuck in unusual places have had an attack of it. Some die pretty quickly afterwards and it is clearly not as a result of the fall. Others battle it and some recover.... but then I have one of the milder strains of the virus.