Gnu, some cookbooks say that if you are going to use a slow-cooker on low, then chicken should be frozen when you put it in. I think this would apply especially to white meat.

I don't bother, but then I rarely put white meat in the slow cooker.

I like to use the Reyholds slow cooker bags because they make clean-up a lot nicer. I've decided that after years of cooking at home, having no TV and driving small, used cars I have saved enough money to spoil myself by buying cooking bags.

Same goes for disposable gloves to avoid touching icky stuff and parchment paper to cut down on grease.