If you have a puppy that is not thriving, acting weak, and looks thin.. try sugar water, use an approprite syringe for the sized puppy.. ie when dealing with teacup sized use a tuberculosis syringe, drop sugar water on there tounge, if they begin to lick, see if they well nurse on the syringe itself.. if so, let them draw on it while you SLOWLY push the sugar water in.. Aspiration is very common and difficult to do this without that happening which will develop into pneumonia killing the pup.
If at all possible help the pup to nurse, that is the best choice, however if they are failing to thrive, it is better to take a chance to save them, than to do nothing.. Keep in mind that nature knows when somthing is wrong and so does the Mother, you will often see the Mother push this one aside while she tends to the stornger ones.. it is not personal, it is nature.. dont over think it and get caught up on that.. just do the best you can and should you see a bubble in there nose you know there is some aspiration.. stop and give them time to see if they start to perk up, keep them warm, cuddled into the Momma’s fur.
If the sugar water seems to help the baby to get more active, you can move to nursing formular, not too hot, not too cool, doing it the same way.. repeat every few hours and check on them often to see if they are beginning to respond.. as soon as they begin to nurse stop feeding and let Momma take over.. there is nothing like nature to know what to do..
Sometimes this is all it takes to get the baby back on track, and sometimes it does not work,.