In a sauce pan over low heat, add the blueberries and stir until they start to pop. Crush then with a large spoon or fork.
Add the rest of the ingredients and combine.
Increase the heat to medium and bring to a slow boil while stirring. Turn back down to low and simmer for about 15-20 minutes, until it has the consistency of barbecue sauce, although it may be slightly thinner.
Brush the chicken breasts with the sauce, cover and refrigerate for an hour.