I just threw uncooked neck bones in the crock pot and only did an overnight on it - is there a huge difference in nutritional yield? it tasted good enough for me and I just drink it - it had an onion and some garlic in it but that's it. I might try longer, bones were grass fed so I didn't think of removing anything (and frankly didn't know it was part of the process)... I want to try with marrow bones too. Is roasting a necessary step?