Okay I had a chicken in my flock whose legs went limp last week, from what I read she may have come down with Mareks disease, so I had Isolated her because at the time I had no clue what was happening and didn't want her getting pecked at while she was immobilized. Today I discovered one of my roos also came down with the same symptoms, I removed him away as well, My question is, all the other chickens seem normal right now. But what measures must I take to avoid having the others come down with the disease? if they don't already have it?