I know this was a couple of years ago, but I'm now experiencing the same with my silkies. I came across your thread and I'm curious to know if any others fell ill. I continue reading online and everyone says if it's Marek's, it's highly contagious. However, no one posts the time line. How long does one bird need to be isolated? What is the window for infection? Are they already contagious when they start showing symptoms? If one bird in a flock kept in close quarters has marek's, is it inevitable for all of them to succumb to the disease? Thanks for any advice.