* Breed: Some breeds are naturally more fertile than others.
* Health: A healthy mare can have more foals than a mare with health problems.
* Age: Mares typically stop being fertile around 20 years old, though some may have foals later in life.
* Management: How often a mare is bred and the care she receives will affect how many foals she can have.
Generally, a mare can have around 10-15 foals in her lifetime, but this number can vary significantly.