* The age of the mother dog: Younger mothers tend to have larger litters.
* The size of the mother dog: Larger dogs may have larger litters.
* The health of the mother dog: A healthy mother dog is more likely to have a larger litter.
* The breed: Some lines of Silky Terriers may be predisposed to having larger or smaller litters.
It's important to note that these are just averages. Some Silky Terriers may have litters of 1 or 5 puppies, or even more rarely, even larger litters.