Frozen Chicken with Pasta Sauce in Crock Pot?

Hi, I was thinking of putting 2 frozen Roasted Garlic Chicken s with a jar of Pasta Sauce in a crock pot. Most of the answers I've read said it's okay to put frozen chicken in a crock pot to cook but the crock pot instructions say not too. Maybe I'm just looking for some reurance so that I do give myself food poisoning!?! Any thoughts? How long would I cook it for and what setting do I use if I do?