Good job on taking over for mother cat for a while at least. Perhaps she will take to her kitten when it looks and sounds more healthy from your feeding it. Please remember to stimulate the kitten to pee and poop since mother cat may well not be doing this either. If this isn't done after feeding, the kitten can die very quickly. Use a warm wash cloth and stroke gently (not too lightly though) down the kitten's abdomen towards the anus over and over until you see it pee and poop.

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