What happened was: we got a bunch of bones from the organic butcher, & froze them to dish out later, & then they all froze in a lump so all had to be defrosted at once. So I figured to use them post-defrosting (since you oughtn't to refreeze meat) by making stock. (Plus I was expecting him to leave some bits of bone behind & wanted to use those.)

Next time we freeze separately :)

They've gone in Marna's bokashi compost which can take meat & dairy.