Ideal hatchery is a professional and caring place.
DO call them and tell them of your problem.
I would wait two days if you have chicks DOA and dying.
I received my Guineas from them Yesterday, all alive and today all doing GREAT. I got seven packing peanuts as well, all doing fine.
EDTA:
when you get your chicks be sure you have a heat source going even in this heat.
The BOTTOM of the brooder should be about 95 degrees F.
Be sure your brooder is large enough for them to get away from the heat source if they find it too hot.
Put down small pine shavings and then COVER this with paper towels for the first 5 days.
The chicks need to know that food is food and shavings are shaving. Rarely though do chicks eat the shavings, but it does happen.
Next, be sure to put some sugar or Molasses in the first water container you give them.
This will give em a boost.
After the first container, start with Apple Cider Vinegar, a small amount, to keep the pasty butt at a minimal.
Be sure to use medicated starter and put it on top of the paper towels for the first few day.
Later you can use a small, shallow dish for the food.