Hi there, TIA BYC'ers for answering my questions. I have a sick 9-10 wk old polish chicken name Polly. On Saturday I noticed her laying down, head down in the large run, but when I went over, she got up and I thought she was fine. On Sunday, I noticed she was spending more laying around, but thought I may have just caught her at her nap times. But Monday AM when I let them all out to forage, she immediately went and laid down, so I knew something was wrong. I brought her in the house and she is in a box by herself. After reading a bunch of posts, I'm concerned she may have a form of Marek's. Here are her symptoms: Lethargic, mostly laying around, head down Green and white, watery poop (from not eating?) Not eating or drinking Moving her head back and forth sometimes, like a tic Looks at things closely, maybe having a hard time seeing? I have given her Poly-Vi-Sol, treated her from worms, and started on an antibiotic (tetracycline). I treated all the chickens for cocci a couple weeks ago, so I don't think it's that. I tried giving her egg and yogurt, she wouldn't eat it. I am hand-feeding her some baby parrot formula, kefir (not near the antibiotic times) and giving her water from a dropper. All my birds get ACV and a vitamin/electrolyte mixture in their drinking water, and I put DE in their coop shavings. I've checked her for mites and lice, she's clean. She is wasting away and I wonder if I am only pro-longing her misery. I want to give her another day or two to show some kind of improvement, and if she still refuses to eat or drink, I don't know that I can save her. But in the meantime, I am now scared half to death about Marek's. She was a chick I bought from an individual and so I have no idea if she were vaccinated. Most of my flock was vaccinated as chicks (the oldest are just over 2 mos old), but some I'm not sure of. The info I've found online talks about vaccinating day-olds or eggs. Right now, everyone else appears to be healthy and I'd like to keep them that way. Questions: Does it sound like she has Marek's or something else? Can I vaccinate my older chicks? If so, how effective would that be? Where do I get the vaccine and how do I administer it? If I'm not sure, is it Ok to vaccinate a bird that had already been vaccinated? I read that exposed birds become carriers, so if she does have Marek's, I'm assuming the few I'm raising for someone else have to stay here? Even the already vaccinated ones? Will the roos eventually have to be destroyed (I can't keep them)? I also read that it's almost impossible to get rid of the virus in the environment. Is it possible to disinfect their coop cages to kill the virus? I have a few Indian Runners and I wanted to find homes for two of them. Do ducks get or carry Marek's? Also, if she dies or I cull her, how do I find out where/how to send her for a necropsy, and how much does that typically cost? I live in Oregon. Thanks so much. I'm a first-time chicken owner and this is so frustrating. First, several chicks got cocci and I dealt with that. Now I have this situation.