your local farmstore will have feed called, chick starter. Whichever type they have will be fine. Others may chime in about organic, medicated, non-medicated, booster vitamins, silky specific ideas, etc. Choose a style best suited for you and your chicks will do fine.
The learning center will have a section to read about raising chicks that will provide basic information about the feed. I started five years ago with chicks after reading that section (and other on line documents) and I have had good results following those practices for my home flock.
I started new chicks last week in the barn brooder where I have had chicks previously, so I chose regular, common, medicated chick starter. I will use that to avoid cocci for about a month to 6 weeks as they are transitioned to the coop. After that time the immune system is more mature and I will wean them off medicated onto regular starter/grower. 'just one opinion. Others will have opinions and methods that are very good as well.