I cant place blame here sweets, like I said they had been shipped too, and I have no clue how live critters get shipped, probably next door to other birds too. some stuff spreads in the air for miles too! I am sorry, not sure what you have going on, chickens are a pain in the butt with illnesses and stuff, thats why there are so many threads going, and the only way to be sure is to get them tested. Kat knows more about this than anyone, some say viral illness is everywhere in everyflock, and some say mareks is as well, I havent a clue!
after losing a lot of birds last year and not knowing what was going on . a pathology report from the state lab said they had it all . some anti bodies read a false positive . If they get it and they live they will test positive for life .so many air born wild bird carried and human carried . it is amazing we have chickens . hard to say how they get sick .could be any of a great number of reasons . problem is they are so fragile to start with everything is almost always fatal sorry Saris