Singletons have a lot against them. It starts in the womb, they get bigger, like a fish that grows to the size of your fish tank, so it's harder to get them out. In addition to this, a mother dog's uterus is usually large enough to accommodate several puppies, so when only one puppy occupies the space, it is believed that it tends to grow larger than the average puppy. Some veterinarians debate this, arguing that singleton puppies are not necessarily larger, stronger, or smarter than puppies born in an average litter.
Sometimes a puppy isn't enough to provide the hormones needed for the mother to go into labor. The next litter of the same female was also a solitary puppy that turned out to be fine and totally normal, except for being a little big for the breed, which is not unusual for singleton puppies. Not all puppies can be seen moving or even felt, especially in deep breeds. I highly recommend checking the puppy to see if it has a viable heartbeat with ultrasound before deciding on a C-section.
Some puppies were born naturally when the female had been sedated and prepared for a cesarean section, the relaxation of the muscles made the puppy easier to release (these puppies had died). Unlike littermate syndrome, single behavior problems are the result of being alone with little feedback and correction. Litter mates are the first teachers of a puppy, one of several reasons why it is beneficial for puppies to stay with their litter for about two months. Some breeders push puppies out of their nipples to imitate what other puppies do, but this is an approach that can be counterproductive.
Spending a lot of time with another litter allows a single puppy to have a more typical or normal experience as a young puppy. The problems that singleton puppies are prone to have are the result of not having been raised in this traditional litter environment. There is a high probability that you will financially need to cover the costs of cesarean section, given that an “unscheduled emergency cesarean section results in a higher mortality rate, realistically reserving an elective C-section “in hours”, which increases the survival rate of puppies and maintains the operating cost to minimal, along with your anxiety and any stress in the woman. With no litter mates around, singleton puppies lose significant tactile stimulation in the form of other puppies that crawl above and below them.
Therefore, if you encounter a unique puppy, work on teaching bite inhibition from the start, handle the puppy frequently to discourage touch sensitivity, help the puppy experience interruptions and frustrations, and most importantly, encourage the puppy to spend time with other puppies in the same age as much and as soon as possible in those first 12 weeks. Because the lack of litter mates can have a big impact on the singleton's future behavior, some careful breeders will try to introduce the singleton puppy to another litter of puppies, hoping that it will be accepted and integrated well. Of course, the ultimate solution to preventing singleton puppies and reducing the problem of pet overpopulation is to sterilize and neuter your dog.