Cook times can also vary slightly according to which size chicken breasts you use. The typical size is about 6 oz. per breast – I use 3-4 breasts when making this Crockpot BBQ Chicken and it ends up being 1 lb. of chicken total. That is the optimal amount of chicken for this recipe, but if you're looking to use less chicken you can use as few as two chicken breasts.   I would not recommend adding more than 1 lb. of chicken to the crockpot as this may throw off the cooking time. It's just good to be aware that you can add up to a certain weight so it doesn't necessarily have to be just 3 or 4 breasts if you are using very small chicken breasts.