There was a question on "The kitchen cabinet" on Radio 4 or 4extra this am to do with making stock from bones - I was only half listening to it but I think that the consensus was that very little nutrition could be obtained from bones so best to cook for a short time only, to extract what flavour you could - then bin them! I speak as one who always intends to make full use of poultry carcasses by adding pulses etc to the water but, in reality, I can't be bothered with it and now I feel vindicated - Yeah! Result.