Hi, I'm new to poultry and got a job where I hav over 20 hens, 2 ducks and couple geese. I hav problem with 1 hen for last 2 weeks. I hade 1 with similar symptoms about month ago and after putting her to quarantine we decided to put her down. This one i have in quarantine over 2 weeks, she is eating like mad. She look healthy except she completely lost balance. I did research on internet and found dozen possible diseases. Also vet looked at her but that time he excluded bacteria/virus infection. He gave me Atb, and she was on them for first week, another vet change atb 4 days ago. I feed her with boiled egg,yogurt,bit of poridge and adding some sea weed. She isnt progresing and she is not getting worse. She just cand stand up and lately just lying(either normally or on side). After posting her video on facebook i got couple replies thats saying its Marek's.. now I'm wondering how long can hen survive with marek. Is there any point to keep her alive or what else i can do...so far no more hens showing any symptoms of sicknes..