25lb Purina Start N Grow Greatness starts on day one. Purina® Start & Grow® Medicated chicken feed contains amprolium (not an antiboitic) to aid in the prevention of coccidiosis. Our feed gives your chicks a strong start and enhances early hen development. Raise chicks from day one to laying age (18-20 weeks) with feed that supports their digestive health and immune function – and aids in the protection against coccidiosis where immunity is not desired.