I would agree that getting a necropsy with testing is best. We read a lot of threads where someone suspects Mareks, and has lost birds, but for one reason or another, they never get it confirmed. Each state can vary prices for a necropsy from $20 up to $150 or more. If a necropsy is too expensive, there are labs that can test blood serum or a feather shaft without doing a necropsy. That can cost $20, plus shipping. Here are 2 links for that:
http://www.vetdna.com/
https://vet.uga.edu/education/acade...ealth/poultry-diagnostic-and-research-center/
http://www.vetdna.com/
https://vet.uga.edu/education/acade...ealth/poultry-diagnostic-and-research-center/