Marek's surviving flock and member.
My best advice is to find somebody close by who would be willing to take your flock for you knowing that they have MD exposure. Why do I say that? Because the dander that causes MD is everywhere and is known to travel at least 5 miles on the wind. I have people next door to me that keep chickens and I've gifted them chickens before knowing I had MD. Birds have done fine as they were resistant.
I also say start with vaccinated chicks and before people start tossing rocks at me for saying that, yes, I know the big debate about vaccines. Yes, I am a person of science. But personally IMHO, what helped me keep a flock that isn't dropping dead regularly is that I hatched local resistant birds from eggs I bought from an Amish neighbors' flock and when I needed or wanted to add birds to my flock, I made sure the birds were vaccinated.
I also went with Egyptian Fayoumis which are genetically resistant to MD. My OEGB Bantams are working on their third generation and knock on wood, cross my fingers and say a few heart felt prayers, I haven't lost one bird to MD from my flock in over 5 years.
Personally it would break my heart to kill all my birds (I have a flock of between 40-50 birds, many of them cherished pets). if we were facing a move but I would definitely offer them to my next door neighbors who also have a growing flock of bantams from birds I have gifted them.
Incase it hasn't been addressed. No, MD does not pass through the egg barrier. Eggs from MD positive hens are safe to hatch. I would wipe them down with a recommended antiseptic for eggs before incubating though. Oddly enough it is thought that resistant and vaccinated hens will pass on resistance to their chicks. Just make sure that both hens and roosters used for hatching are over 3 years of age, the older the better.
Please feel free to read my article about my adventures with Marek's disease:
https://www.backyardchickens.com/ar...-i-learned-to-deal-with-mareks-disease.76944/