* Age of the mother: Younger mothers may have smaller litters, while older mothers may have larger litters.
* Overall health of the mother: A healthy mother is more likely to have a larger litter.
* Genetics: Some Border Collie lines have a predisposition to larger or smaller litters.
* Environmental factors: Nutrition, stress levels, and overall health of the mother can all influence litter size.
It's important to note that:
* It's not uncommon for Border Collies to have litters of up to 12 puppies, although this is less frequent.
* Litters smaller than 3 puppies are considered unusually small.
If you are thinking about breeding Border Collies, it's essential to consult with a veterinarian and a reputable breeder to ensure the health and well-being of both the mother and puppies.