@charley
Rendering one wolf at a time in an empty scene with the default HDRI loaded and nothing else was fine. And running the dforce simulation before hand didn't cause any problems at all.
However, I noticed that whilst rendering my pc started to use an additional 14GB of ram, on top of what it was already using, and my GPU ram shot up to 17GB in use. Crazy for one wolf in an empty scene.
Trying to render all 4 wolves in a scene was hopeless, Daz completely froze and crashed. I'm guessing I ran out of resources?
I used the wolf assets from this bundle:
Folklore Battle Bundle + extra*
Hope this helps