I brought home 3 babies and kept them separate from my 5 hens. They are only separated by a wire fence but have separate coops too. One of the babies - now 11 weeks- developed all the signs of Mareks. (paralysis, etc.) We culled her today but I am worried to death about my hens and the other two babies. No one was vaccinated. I know better now. If I lose my whole flock, does the disease ever go away? Can the area be sanitized? What should I do?