What is a one-sentence summary of the following article?
If the mother dog is pushing one particular puppy away, instead of drawing him near her, you should be concerned. A puppy not huddled up with littermates and his mother will not get the food or warmth that he needs to thrive. A newborn puppy can become a weak puppy within a matter of hours. There are certain signs to check for to see if your puppy is having serious problems such as:  Cold to the touch or cold mouth Weak suckle reflex when the fingertip is gently placed in mouth Limp or poor muscle tone: head hangs down and legs don’t pull back when lightly tugged Inability to nurse Feces on the rear: can indicate diarrhea (a serious issue) Discharge from the umbilical stump Non-stop crying You should check all your puppies’ weights on a suitable scale twice a day. Kitchen scales will do, as long as you clean them well afterwards or even use them just for puppy weigh-ins. The weight can be taken in grams or ounces, just be consistent. They should never lose weight, instead they should gain about 10% of their birth weight each day after the first day of life. This indicates they are getting enough milk. Weights should be recorded in a notebook or spreadsheet so you can track their progress for the first two weeks of life.

Summary:
Make sure the mother dog is taking care of all of her puppies. Look for signs of trouble. Check puppies regularly.