I have defrosted directly in water (you end up with a wet rodent) and in ziplock bags. With larger rodents, I have found it alot easier and quicker to put the frozen rodent in the fridge in the morning so in the evening it will be mostly defrosted when you place it under warm water or under a heat lamp before feeding. Be sure to slightly squeeze around the base of the head and the fattest part of the stomach....these two places are usually the last to thaw out. Hope that helps.