So this is the 3rd week one of our girls has been sick. We noticed her having problem with one leg like it was very weak. We isolated her and went to a vet 4 days later when she didn't get better. While we were there she started to be clumsy and trip over her feet. He said probably Marek's. She tries to walk and steps on her feet and falls- can't stand tall for more than a second. My concern is it's now week 3. She's still getting around some has no other symptoms and is eating and drinking- but feels like she's lost weight. She is very chatty and likes to be held. We're concerned with our other 3 chickens getting it. They are all 9weeks old (even the sick one). We've tried antibiotics and an anti inflammatory. I can't find poly vi sol without iron- was going to give it a try. We aren't looking forward to it but is it best we put her down now so the others don't get it? She's still isolated and in the house.thank you.