What to do with Bones

I am always making soup and stews, slow cooking whole chickens for the broth. I've always thrown the bones away but it feels wasteful so I'm finally searching for a purpose for them. Does anyone here know if, by the time they've been cooked in a broth for 24 hrs is there any nutritive value left in them? Should I crush them into a mash to supplement my dog, cat and chicken feed - they seem soft enough to not cause any damage?

I do two things with my spent bones (chicken, duck, rabbit, lamb, beef, mouflon, pork, goat).
1- feed them to our big farm guard dog. He's the one dog that we have that finely chews all his food, bones included. So he's often the lucky recipient of the tasty bones. Yes, it's risky feeding him bones but so far he's managed 8 years ok. Yes, he could crack or break a tooth, get an internal obstruction, but I consider the risk is low. He's much more likely to get kicked by the horse or rammed by the sheep. And he clearly enjoys those bones.
2- process them through the wood burning stove then crush them for a soil amendment. All the big bones go this route. I get a pickup truck load from time to time from the local cattle ranchers. It's not uncommon for a cow to die out in the fields, so I can go harvest those bones when the time is right.

Here's an article describing How To Make Your Own Bonemeal Fertilizer
Step 1 is gather bones
Step 2 is clean them by cooking. If you are using them for soup stock, you're already up to this step
Step 3 Dry.
Step 4 Grind into powder

Engineers Without Borders has a biomass grinder which I think would handle grinding of the bones.



For the plants to make use of the pottassium, the soil will need a slightly acidic pH.
Add some rotted pine needles.

Here is the open source file (2.5MB PDF) for plans and drawings of the grinder depicted above.

This is great - thanks Ken and Su. I've always wondered if bone meal is a DIY option - it's ridiculously expensive to buy. But I just have this impression that anything cooked that long would have all the good stuff leached out.

Update, I tried running small well-cooked bones through my food processor but only half would chop, the rest just spun around and got stuck on the blade. I'm going to try again after drying the bones as recommended in the first link. And I just took time to look at the plans for the biomass grinder. What an amazing contraption - could this also be used for shelling sunflower seeds I wonder? They call it an "Easy DIY" grinder. Yeah right. Ken have you made or seen one? I need to find some boyscouts to try it as a project for a badge - lol! Or not to be sexist, some girlscouts

I haven't looked into that bone grinder because I really don't need it. All the bones destined for my garden are processed by fire. I use wood fired stoves to heat the house and another to cook livestock food. So bones just go right into the burn chamber. When they come out with the ashes, they are often brittle and crumbly. Small bones break up nicely with just my hands. Bigger bones get smashed with a hammer. If they are still too hard to smash into smaller chunks, then they go back in the fire for a second round. I don't bother to smash everything down to powder, but I do get a goodly portion of powder and grit. If it's less than an inch, that's fine by me. I don't mind chunky bone as a soil amendment. It works just fine with my soil conditions.

With poultry bones by the time I've finished making broth the bones can be mushed between fingers. I add them straight to my compost. I rarely have larger bones around, when I do they often turn into craft materials.

We save our bones in the freezer as we make them from eating certain things, like chicken, over several weeks. I make stock, and then the bones go in the woodstove, then the ashes to the compost. If we have some smaller bits of bone, like from a salmon, it goes straight in too. Just to add in too, we butcher most of our own meat, and always use butcher paper. It is awesome. The food stays fresh, no smelly garbage to deal with, as the paper gets burned as well. Meat should never touch plastic!

I use a pressure cooker to get all the goodness out of bones, such that they crumble in my fingers afterwards. Still, there's calcium there, so I chop the mess of bones with a spatula and throw them into the chicken pen.

I have placed dried bones in a metal container and then used a sledgehammer in the same sort of motion that you would use if churning butter. The only moving parts are my arms. It's hard work, but it reduces the bones very quickly.

A garden hammermill does a great job of breaking down bones.

A cement mixer can be turned into a ball mill, with the addition of some cast-iron window weights or other large metal chunks.  This method can be used to break down glass, soft rock,  and many other materials.

I bury bones and carcasses in the food forest. I typically put them near the drip-lines of trees. I put them just deep enough that I won't disturb them if I decide to weed or cultivate.

THis is a great thread! I've wondered about what to do. Thanks for giving so many great ideas.
John S
PDX OR

Yes, I bury mine too. I think that seems the most natural. But I really like the idea of grinding it up, and then feeding it to the chickens as a supplement.