If you have the energy and time, I think container plants would probably be easier to provide for by simply hard-boiling the bones after you have finished with them for culinary purposes (large stockpot all day) and then using small amount of the cooled bone-broth diluted in water. You can add eggshells to this, too if you want. If you have somewhere that you can dry out the thoroughly cooked bones, they do crumble easily and that's your basic bone-meal.
I have to admit I don't always take the time, but when I do, I usually bury the crumbly bones and scrap bone-broth (this is not the good-tasting kind) mixed with kitchen scraps in the bottom of the outdoor compost pile (when I turn the entire pile) or in-ground big tree, etc. large plant planting holes. Both the broth and bones will spoil easily and smell, so you will have to keep them frozen if not using right away.
I don't have a secure place to lay out the bones to dry out (cats , etc.) and I don't have spare space in the freezer or refrigerator, so I tend to just use the compost pile --- actually bokashi fermenter too (this is an anaerobic process and maybe similar to tomc's?) --- as a place to finish turning them into plant-available nutrients.
It's tricky putting organic home made fertilizers in containers because the volume of soil is not big enough to buffer and support out-of-balance microbial activity if you add too much -- it's like small aquarium tanks being difficult to keep in balance. You won't want stinky containers and soured soil will be bad for the plants and will force you to repot with fresh potting mix. I think it does help to put some earthworms and compost worms in each pot -- they can help manage the system as long as you don't accidentally kill them too....
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