Normal litter size can range from 1 to 12 puppies, with 5-6 puppies on average across all dogs. Whether Fluffy has three or ten puppies depends largely on their breed. Some breeds are known to produce large litters, while others are more conservative. As a general rule, you should expect smaller litters in smaller dog breeds and larger litters in larger dog breeds.
Typical litter size tends to range from 1 to 12 puppies, with an average of 5 to 6 puppies in all dogs. However, large breeds can have up to 15 offspring. It's a wide range and depends on your dog's species, size, health, and pregnancy history. A younger stallion is more likely to produce high-quality sperm, which in return can result in a larger litter size.
I think that the timing of reproduction also matters in the factors that affect the size of the litter, as well as the case of the absorption or abortion of some fetuses by the mother and I would not know if the size of the litter can really be hereditary, I would like you to research more on this. This will not only allow the veterinarian to count the number of puppies present, but also to inspect their bone structure and observe any abnormalities. Heritability has approximately 10-15% influence on litter size, meaning you can't rely on genes alone to increase litter size. Even though these tiny puppies are adorable, an extremely low weight puppy has a higher mortality risk.
A healthier, thinner female is more likely to have a larger litter than those who are overweight. The bottom line is that influencing the size of a puppy litter is almost impossible if you want to do it precisely. For example, some animals (humans, elephants and hippopotamuses are some of the best examples) tend to give birth to very small litters, made up of one or two individuals. I once had a relatively small chocolate lab that produced a litter of 9 and a litter of 10, which proved to be quite difficult.
Determining litter size can help breeders know if the mother dog has given birth to all puppies and recognize early signs of possible complications, such as large puppies that may be difficult to transmit. Let's say that for your breed the average litter size is between 8 and 12 puppies, some breeders want to help their mother reach 11, 12 or even 13 puppies. For example, spaniels and retrievers usually have four to eight puppies at a time, while smaller dogs, such as terriers, can only have two, maybe three in a litter. Adding a little more protein or additional protein supplements to the diet during pregnancy will greatly reduce the chance of having a smaller litter.
Now, even if it is extremely difficult (if not impossible) to actively determine and decide the size of your next puppy litter, several factors can more or less heavily influence the size of the dog litter.