Here's why:
* Genetics: Pitbulls, like most dog breeds, have a specific genetic makeup that dictates their coat type and thickness. Some Pitbulls have thicker, more "hairy" coats, while others have thinner, smoother coats.
* Seasonality: A puppy's birth season doesn't affect their coat. The weather conditions might influence their coat growth rate initially, but their overall coat type will remain consistent with their breed genetics.
However, there is a slight possibility of a winter-born Pitbull having a thicker coat. This could be due to the mother dog's hormonal changes during pregnancy, which could slightly influence the puppies' coat development.
Overall, the hairiness of a Pitbull puppy is primarily determined by its genetic inheritance, not the time of year it was born.