I've often followed
Meyer Hatchery's feeding guide and have had great results. Scroll down on that page a bit to see the feeding chart.
As for medicated vs. non-medicated, that is up to you. There are many threads discussing it here on BYC if you want to search it up. I personally don't use medicated anymore because I've had good results with gradually introducing the chicks to outside bacteria. For example, I'll place small chunks of dirt and grass from my yard in the brooder, gradually adding bigger pieces and then also letting them to little field trips outdoors. They build up natural immunity to bacteria and cocci that might be present in my yard before I put them out there.