Sorry to hear about the possible Mareks. It is not the end of the world, though. you may lose a small percentage of birds, but most of them will develop a resistance to it, (I am told.) I was devastated when I lost my first bird during my first year of having chickens, Eventually you develop a bit more realistic expectations and accept a loss now and then. Everyone thinks that they will be different because they will take really good care of theirs and they will live really long lives. But alot of it is really out of your control and all you can do is the best you can. It is just the way things are. There are just too many things to go wrong. Wild birds spread disease all over. Everything wants to eat your chickens.
Hugs and I hope she gets better. but if not...you are not to blame
Hugs and I hope she gets better. but if not...you are not to blame