I am happy to report that my frozen chuck roast is doing wonderfully in the crock pot. The house now smells like fajitas. It has cooked just fine and should be fork fall apart in another couple hours.
As for chicken, I would only do boneless in the crock pot. I think if you put it in the crock with a good amount of liquid in the morning before you go to work it should be fine. Maybe you needed more liquid in it last time? Unless I am going to be home to check the moisture levels, I tend to over liquid my crock pock adventures.
Try boneless chicken (white or dark meat), some Pic Sweet seasoning blend, a clove or two of garlic, thyme, and a bay leaf, equal amounts of chicken broth and water to cover. Set it on low and go off to work. When you get home fork shred the chicken, put it on high (add more broth if needed), then when it heats up to high, drop spoonfuls of biscuit dough on top, recover and cook until the dough is fluffy. Yummy.