I sear the beef bones and then put them in a roaster psn. I cook them at 450 for about an hour and then add water, etc. and cook that at 250 overnight. I do the same wirh chicjen, Turkey, lamb and pork bones. I break the poultry bones. I end up with "jello". My secret ingred for poultry stock is pickling spice. Until I started roasting bones, my stock was meh. I just coukdn't get the depth of flavour. Yes, it takes two days, but it is worth it. I worked at a restaurant where it took 3 days to make gravy...I stop after day 2 when making stock.