Brothers Rob Gronkowski, Gordie Gronkowski, Dan Gronkowski and Chris Gronkowski at The 2015 ESPYS at Microsoft Theater on July 15, 2015 in Los Angeles, California.

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Dan, who runs Gronk Fitness along with Gordie and is responsible for e-commerce operations, also has his own project called Herd Chew, an all natural replacement for chewing tobacco made with Valerian Root and White Willow Bark. "We just keep coming up with stuff," Dan Gronkowski, 33, tells CNBC Make It with a laugh. So where do the siblings get their hustle from? Dan and Chris say they picked up their business acumen from their dad, Gordon Gronkowski, who was an entrepreneur himself. "He started a business in 1990 called G&G Fitness Equipment out of Buffalo, [New York]," Dan says. "That was when we were a young family, and [he] put all of his money in, was working two jobs for probably eight or 10 years to get the business going. "We were always around the stores," Dan says. The company now has over 80 employees and store locations along the east coast.