First off—if the kitten is breathing but cold, hypothermia's the threat, so warm them slow, no feeding till 95 degrees Fahrenheit or above. Normal temperature for a kitten this tiny is 99 to 105 degrees Fahrenheit or 37 to 38 Celsius. Never rush; this could take up to 3 hours. Once they are up to about 99 degrees, you could try a fingertip dipped in warm sugar water, to moisten their gums and to help ward off hypoglycemia. Caution is key.
Below are a list of options for slowly reheating a neonatal kitten.
Option one: Heat disc heated in the microwave for about 4 minutes, towel or soft baby blanket -wrapped, kitten on top—flip front to back every fifteen seconds, 1 to 3 hours or as long as it takes.
Option two: Rice sock—cotton sock, three-quarters uncooked rice, microwave 60 to 90 seconds, test on your inner arm, knot tight; same rolling through towel.
Option three: Rubber hot-water bottle, half boiling water, cool thirty seconds, thick towel wrap—flip the kitten often.
Option four: 2 or more sturdy plastic bottles, hot water, wrapped securely— put the kitten in between and keep moving them around.
Option five: Chemical hand-warmers in socks or fabric, triple-wrapped—no direct skin—gentle rotations.
Human skin's handy for transport, but too cool for full fix. Stay patient, watch for purrs, squeaks or moves. You're heroes saving these tinies!
Which options have you used? How long did it take to warm them?