Place chicken in the bottom of a 6-quart crock pot. Whisk together remaining ingredients in a large bowl then reserve 3/4 cup and pour the rest over the chicken.
Lift each chicken breast to make sure some of the sauce has gotten underneath then place a lid on top and cook on low for 4 hours or until the chicken shreds easily with a fork.
Shred chicken then return to the crock pot and cook on low for 30 minutes. Transfer shredded chicken to a separate container then mix with reserved BBQ sauce and serve.
Notes
You can use 2 cups of your favorite BBQ sauce instead of making the homemade sauce.
The USDA recommends thawing meat before cooking it in the crock pot.