Preheat oven to 400℉ and line baking sheet with foil
Coat bones and chicken pieces in avocado oil, salt and pepper. Transfer to baking sheet and roast in oven for 45-60 minutes or until everything is golden brown.
Chop vegetables and aromatics into small to medium pieces and transfer to cooking vessel with herbs, salt and peppercorns.
Allow bones and pieces to cool slightly before transferring to cooking vessel with vegetables and herbs. Scrape browned bits off foil left from roasting chicken pieces by adding a little water to sheet while it is still warm, gently scraping with a wooden spoon.
Transfer water and fond from sheet pan into cooking vessel with everything else and add enough filtered water to cover all ingredients.
Pressure cooker method: close lid and set to the stock setting or high pressure for 45 minutes with natural/slow release. Stovetop method: cover and simmer on low for 4-6 hours stirring occasionally. Do not allow to boil, this will produce cloudy stock.
Place cheesecloth or fine mesh lined colander in a large bowl that will accommodate all the stock and ingredients.
Once cool enough to handle strain pot contents and use cheesecloth to compress solid ingredients and squeeze out remaining liquid.
Store in fridge for 3-4 days, freezer for 3-4 months or pressure canned for up to two years.