Please google pictures of Marek's disease to determine if your hen has it, because it has a very distinct appearance, and you hen may have something else. I would not assume she has Marek's if she doesn't have the characteristic "hurdle" stance with one leg front and one leg back.
Not all chickens with Mareks have the characteristic stance. Probably most do, but not always. It usually hits the left leg, then the right, then the wings, then the neck. However it can come in any order. I really hope that her hen doesn't have Marek's, but paralysis is a strong indicator. Marek's is one of the most common chicken diseases in the world. It is common for a Mareks sufferer to be unable to walk or limp, but be perfectly happy to sit in one spot and eat and drink in a nice comfortable spot. My poor Mildred laid on her side for 3 weeks. She cooed at her friend Buffy (who stayed by her side outside the dog crate the whole time) and ate and drank like nothing was wrong. Mildred now runs around the yard with everybody else. She limps and has never been able to keep weight on very well, but she seems content.