good suggestions by dlhunicorn..
until you are able to get the things suggested..you might try some unmedicated chick or grower feed with mixed with plain yogurt, some cooked chopped egg yolk, a little finely grated apple or chopped tomato.
the layer feed is better then scratch corn right now..since his system might have digestion problems.
he was cold, hungry, and probably traumatized..
he needs hydration, warmth, TLC, quiet, and some good nutrition (such as protein)
if he won't drink on his own..give water with electrolytes by drops on the side of the beak
how are his droppings?
keep an eye out for odd droppings, wet or swollen eyes or head, mucus, head shaking, or breath sounds , such as a wheeze.
try and get some Tylan 200 injectible or Tylan 50 injectible and some syringes in...(smallest syringes you can find..1cc. and 25 gauge needles, or insulin syringes, and alcohol wipes)
good to have on hand for respiratory illness.
can be found in farm/feed/livestock supply stores in the livestock section.