Marek's Disease

Marek's disease is a herpesvirus causing tumors and paralysis in chickens 6-30 weeks old. Classic sign: one leg forward, one leg backward (the 'splits'). Highly contagious via feather dander and persists in coops for years. No treatment. Prevention: vaccinate day-old chicks at the hatchery — request the vaccine when ordering. Adult birds cannot be vaccinated.