My flock has been fighting Infectious Bronchitis. When one chicken got sick 2 weeks ago, my vet reminded me that symptoms could returned if the birds are under stress. A few days later, a laying hen died. That was two week ago. Then the rest of the flock seemed to be getting sick. It didn't make sense because IB was supposed to come and go with symptoms but I didn't think it would go through the flock again. Fast forward to a few days ago. The juvenilles who are about 17 weeks old starting acting sick. Again I brought out the antibiotics and they seemed to be doing okay except for clairebear, my blue silkie. She was very thin which is a sign of IB. I'd been weighing her and she had gone from 1.15 pounds to 1 pound. Her leg was acting funny. I thought her body was shutting down because she was dying. She eats like a fiend when I put food in front of her, but she cannot walk or sit unless I prop her up. I went to check for a broken leg a bit ago and found my silver laced polish (same age from same place as babies).. the polish was laying on her side.. sprawled out like she was sunbathing without the sun. I brought her in and I am letting her eat. Her legs are very weak. Claire is in a separate temp coop near the others. The advice I need is this.. do I keep them alive? I know that sounds cruel, but I have some hens that are almost a year old that I am very fond of. They have been in the same coop with the ones who are sick.. eating same food.. sharing same water. Are they all infected if this turns out to be Mareks. Will the older ones become paralyzed too? I know the rule is to separate out the ones who are sick but at this point I just want to try to save my favorites by separating them from anything that might be remotely sick. Claire's right leg seems a bit stronger but the left one can't hold weight at all. The polish is now standing and eats treats. She eats like a fiend, but has gone from 1.75 to 1.5 pounds in the past week. With this being a leg issue, my mind went to possibly Marek's disease. Can anyone advise me on how to continue?