Eight and a half hours on low is too long to cook two bone-in skinless chicken breasts in the slow cooker, even if they are just barely thawed when you put them in. I didn't think it was possible to dry out meat in a slow cooker. I was, apparently, wrong. At least it was tasty, if dry.
So for future reference, here's what I did: two breasts, covered with a cup of chicken broth mixed with half a packet of taco seasoning. I think seven hours would have been plenty for these; maybe even six, but I was not at home to check. I'll try it on a weekend next time. Still, the ensuing chicken shredded up in tacos was very tasty - it just needed the salsa and sour cream to make it edible. I wrapped up the rest in a tortilla with cheese, tomatoes, lettuce, salsa and ranch dressing for tomorrow's lunch.
The next slow cooker adventure begins Friday, when I will try not to overcook two pork tenderloins done Southern pulled BBQ style. Tomorrow night Chris is cooking - falafel patties in pitas, from a Cooking Light recipe. I am excited.