Hello, Melissa, and welcome to BYC! Glad you joined.
Have the chicks been exposed to the soil yet?
I would offer a waterer with just plain water in it too.
Hi Melissa, welcome to BYC. If they have been exposed to soil, they may have cocidosis.
I'd pick up some corid while you are at Tractor Supply. It's good to have on hand. Also, I'd be careful with the human supplements. Rooster booster and Poultry Cell both have good vitamins for chicks. A scramble egg can do wonders for them, and has selenium in the yolk.
If you can't find the supplements above, you can get Poly-vi sol without iron, for infants. Just drop a little on top of his beak daily.
Good luck. Keep us updated!