You don't even have to defrost, just toss that chicken in there. The skin will not get crispy, it will be gummy and inedible, but the chicken will be so tender and juicy you will not believe it. I cook mine on low, 8-9 hours does the trick. Pop it in before I leave for work, come home, make some instant mashed, open up a bag of salad and dinner is on the table!