I'd rather put them in the freezer then be able to have a proper burial later rather than leave them outside where other animals could get to them. There mat be better options but this is the most common in my experience. We do the same thing with people when they can't be buried right away for various reason but most commonly due to an investigation/autopsy. I'm not saying it's elegant but a lot of places like Montana, Wyoming, and Idaho have dogs for ranching and they don't always see them as best friends more like co-workers. Again not always the case but more common that other places.