Best way to macerate in the cold?

I recently found a bunny dead on the road that was in good enough condition to preserve so I got to work. I removed as much of the flesh as I could and have been keeping it in a bucket of water to soak the rest of it off before I begin work on the bones. Despite being in the water for about a week, very little has fallen off, which I suspect may be due to the dropping temperatures. It has rapidly changed from 60-70F average to 20-40F in my area since I began working on the bunny. I store it outside mostly because of the smell. Is there anything I could do to speed up this process, preferably outdoors?