I purchased 5 chicks from a local store and the said they were vaccinated when I asked, but didnt specify for what. I asked what they recommended for feed and they sold me a bag of Purina Start and Grow Medicated. If they are already vaccinated for Cocsidosis, would it hurt to keep them on this feed? How long do they stay on medicated? I would like to have them on a solid non medicated, but if its better to stay on a medicated.... Thoughts?