Young, small pups can deteriorate fast. The term used to describe this is Fading Puppy Syndrome. We would always recommend speaking with your vet if your feel your pup has an issue. We are here as breeders to support other breeders. We are here to help trouble shoot and offer practical advice.
Not every baby can be saved, but some puppies are lost when an easy fix could make all the difference. For example puppies may stop feeding and fade for various reasons such as dehydration or hypoglycemia. Without intervention these babies will stop feeding, grow weak and die. However with early intervention and prompt treatment these babies can recover and thrive.