I honestly don't know about Mareks and eggs from birds that are carriers. There are a number of nasty diseases of poultry that can leave survivors and they remain carriers for life. If Mareks gets into your flock you can have devastating losses. Birds will be survivors but will infect any new birds or chicks you bring on to your property. Maybe someone else knows first hand knowledge about Mareks, NewCastle, and if it affects eggs? There is lots of information to google but first hand knowlege is best in my opinion.You just reminded me of a question I was wondering about. Can hatching eggs bring things into your flock? I mean, can the chicks that subsequently hatch from those eggs carry diseases? There are many times on BYC I have heard similar stories about people bringing in adult birds from somewhere, and Armageddon of diseases break loose. Makes me think I would never want to bring in an adult bird.
MB