So sorry for your loss. I use Gatorade, Pedialyte or even water with a little sugar in it for a chick-pick-me-up, or Poly-Vi-Sol WITHOUT IRON in some water. I also use the Sav-A-Chick. It has vitamins and electrolytes and have used Nutri-Drench for poultry..
Definitely be in contact with the hatchery and let them know. As much worry and potential heartbreak as it would be maybe a replacement order would be an option.
So sorry for your loss of the babies.
One thing I do when I first bring chicks home, is give them garlic, apple cider vinegar, a little sugar, and avian vitamins from Walmart mixed in their water.(4 cloves, half cup of sugar, tbl spoon of ACV, and follow vitamin directions all into a gallon) I usually give them this for the first 2 weeks, and I've seen a huge decrease in loss of babies. Especially sick or lethargic ones. You can never really tell with them though positive vibes and good thoughts sent your way!