Unless something bad happens, they might not need anything else. Maybe a wormer, if you keep them a long time. You might have a higher incidence of worms where you are.
I like to make sure they get other foods, especially green feed. That offers more vitamins, minerals and phytonutrients. They're healthier, that way. Mine can free range in the growing seasons. In the winter I offer some sprouts, wheat or other grasses and alfalfa. Even a little free range time is good for them. Otherwise, you can grow things to bring to them. Dark leafy greens are good, too. I have those, clover and berries growing for them, as well as other foods.
For a minor injury, I just apply a little plain Neosporin that doesn't have any pain relief in it. Or, you can spray it with some Blukote, if you think the other chickens will be attracted to the wound and peck at it.
I offer dust baths to control external parasites. At least one is undercover, to keep it dry.
I like to offer some sunflower during a molt. They eat a lot of insects here, too.
For chicks, I start at about a week old. I chop things very finely and only offer a bit. They can handle larger pieces and larger amounts as they grow. It's better to only give a tiny bit of other foods, to start.
Give them the once over every day. Notice if their behavior seems off or if you see something different about the way they look. If you ever do see signs of illness, you can see about diagnosing and treating the illness, then. It's pretty easy to pick something up after you know what you need. If you bought healthy chicks from a good source, chances are you'll never need anything else.
