Combine the beef bones, chicken, turkey and beef pieces and place into the large pots. Fill with water.
Bring the pots to a boil for about 30 minutes. Skim off the foam that developes.
Add the celery, carrots, onions, bay leaves, parsley, and garlic.
Bring the pots to a boil and boil for 12-14 hours. During this time add the salt and pepper.*
Add water to keep the level of water until almost at the top of the pots.
Once the 12 to 14 hours is done, strain the cooled stock through a fine mesh strainer, such as a chinois.
I usually take the meat, chicken, turkey and beef, and freeze it for soup later. Discard the bones and vegetables.
Bring the stock back to a boil and reduce as needed. Taste multiple times to determine the need for more salt or a thicker stock.**
Once you have finished the stock, you can place this into quart plastic containers freeze and if you wish vacuum pack.