I had to look it up a few weeks ago.
I don't have details on rats, but I was able to save two baby mice (they had fur, but mostly closed eyes - slits?). These guys are thriving now. Try some puppy or kitten formula, or try "milk" out of soaked oats. I used raw goat's milk - but you may not have that.
A tiny artist's paint brush may be better accepted for delivery than a dropper or spoon. Be Careful! You do not want any fluids to touch the nose - approach from under the chin. This may sound obvious, but my eyesight sucks, and I needed some trial and error, plus a magnifying glass to get that right.
Keep temps up. I actually kept mine for a few days in the heated snake enclosure in a ventilated tupperware type container. (Weird, yeah, but the snake wasn't interested.)