Place chicken carcass to a large stock pot, then add the carrots, celery, onions, and garlic around the chicken. Sprinkle oregano, parsley, thyme, peppercorns, salt, and bay leaves on top.
Add water and bring to a rapid boil over high heat, then immediately reduce heat to medium-low. Simmer for 3½-4 hours, stirring occasionally
When the meat is falling off the bone, remove from heat. Carefully strain the contents of the pot to separate the liquids and solids . Reserve the liquid and the larger pieces of chicken. Store chicken separately in the refrigerator or freezer to stir into soups later and discard the remaining solids.
Allow broth to cool and transfer to airtight, freezer-safe containers. Freeze for longer term storage or store in the refrigerator for several days before using. Enjoy!