I just thought I would let you all know that making bone sauce isn't foolproof. At the least, you should make sure to follow Sepp Holzer's more specific instructions on how to make it, and ignore the overly simplistic instructions posted on this site.
I followed the instructions and video found here and ended up with a great deal more "sauce" than seemed normal. More than an inch deep in the bottom pot. I am guessing that is because I used fresh beef femur bones which have a great deal of marrow in them. It was black and nasty and smelled as described, but it clearly had a high fat content. In cold temperatures it coagulated. Nevertheless, because it smelled so bad, I figured it would work fine, so I slathered the stuff on my apple whips a couple of months ago, and no deer have touched them. However, at some point, someone with a decent sized dog wandered by my orchard, and the dog attacked my Dabinett whip, perhaps thinking it was a tasty bone, and snapped the whip off. I know this, because there were paw prints in the mushroom manure I had spread around the tree for the winter, and I live on a remote island where there are no predators and the largest animals are deer.
So be warned. Someone was mocked on here for suggested dogs would find the smell appealing, and well, she was right. Today a neighbour came up to the island with a small dog, and the dog immediately sniffed around the tree with great interest and then took a leak on my Ashmead's Kernel whip. (It was then that I discovered the destroyed Dabinett.)
Now that I have read Sepp Holzer's Permaculture book, it seems the process for making the "sauce" is a little trickier than I was led to believe. The bones are supposed to be dried and the fire is supposed to be kept to a minimum intensity. It doesn't say anything about what kind of bones to use, but my experience would suggest using smaller bones without a high marrow/fat content.