I've had good luck w/a 4 to 6 lb. turkey breast in the crock pot. I add about 1/2 cup of broth, put some celery, onions & carrots on the bottom, a couple of bay leaves...sprinkle some seasoning over it & cook on low for about 6 hours...tender, moist & slices nicely. You can add potatoes too but we prefer mashed with it. Then I make gravy by thickening the juices. I've never cooked a frozen breast in it...maybe that accounts for the uneven cooking?