No one can give you a definite answer to this question, but there are some suggestions that may help. If the kitten is very small (less than 3 weeks old) and not eating on it’s own, then keep an eye on its eating habits during the first three days of life. You might find that it doesn’t eat anything at all for part or all of those first few days. A hungry kitten will be active and quite vocal when feeding time comes around (this is nature’s way of telling us they need food). At about 2-5 weeks of age, you should start checking more often if your little one has kept losing weight without eating much or at all. By 5-7 weeks old, your new kitty will demand daily feedings with no fail!
If your new little feline friend is really struggling to keep up with his/her energy needs by 7-10 days old, then contact a veterinarian immediately as their condition could indicate something serious like kidney failure or severe dehydration.