I chose not to use medicated starter for mine the last couple of years of pullet starting, as I was hoping to have near-organic free range hens, with no antibiotic if possible. If that's not an issue for you, then you could get the medicated feed. Be sure to supply some source of probiotics as well, as the antibiotic depletes both good and bad bacteria. Depending on the hatchery where your chicks come from and if it is disease-free or not, would make a difference to whether you want antibiotics or not. I don't know the symptoms of coccidiosis or pullorum or anything else.
Might get a Vitamin D3 capsule, prick with pin and mix some with a bit of the yolk and try to get the chick to take some. It's usually in oil and you don't want it to get in the nose I'd imagine, so mix a bit with the egg. Might separate the chick and keep warm especially if the others step on her in the box. If you've seen her drink, great, make sure she does it occasionally, and if not, try to get her to drink. She should follow your finger or the other birds example dipping, but if not try barely dipping her beak in, or get her to peck a drip off your finger. Anything. Maybe a drop of honey with a bottlecap of water for a little pickup. Try getting her in the sunlight for a while too. My old neighbor used to have me mix black pepper with egg yolk to feed the babies, but not the first day or 2, and I don't know what other experienced folk would tell you about that! I only know what she did! I tried it once and it sure didn't seem to hurt them. She used to say it would liven them up or give them 'vitalicky' (but she also had some old wives tales ;-) ). Hope all is well with your chicks! God bless!