Use a stock pot that is tall and narrow to help slow water loss from evaporation. If you have a pasta pot with a strainer, this is great pot to use to separate bones and vegetables from finished stock when done cooking.
In a large stock pot over medium-high heat, place the prepared chicken carcass (I usually break the carcass into smaller pieces to fit into the pot easier). Add chicken onion, garlic, carrots, celery, salt, pepper, any additional vegetables, and enough water to completely cover the chicken carcass.
NOTE: If you are preparing homemade stock for use in a recipe that calls for reducing the liquid, such as risotto, use less salt so it won't over-whelm the finished dish.
Bring the water just to a boil and then reduce heat to a slow simmer. DOT NOT COVER THE POT. Let simmer approximately 60 to 90 minutes so the stock can reduce and concentrate its flavor. The key to a good stock is to bring water to a boil just once at the beginning and then cook at just barely a simmer for the remainder of the cooking time, as long slow cooking is best to extract all the subtle flavors. Chicken stock can take anywhere from 1 hour to 5 hours (if you're using a Slow Cooker). Remember, the longer you have to let the stock simmer, the richer and more nutritious it will become.
Use a large 7-8 quart slow cooker and pre-heat on high heat.
Place the prepared chicken carcass (I usually break the carcass into smaller pieces to fit into the pot easier). Add chicken onion, garlic, carrots, celery, salt, pepper, any additional vegetables, and enough water to completely cover the chicken carcass. Cover with a lid and cook on high heat for 4-5 hours or low heat for 8-10 hours.
After cooking, remove the pot from the heat or turn off the slow cooker. Remove and discard the chicken bones, vegetables, and any meat pieces (since you have cooked the mixture for a long time, there is no nutritional value left).
Strain the remaining liquid to remove smaller particles in the stock (pour the liquid through a fine mesh sieve place over a large pot). Be careful as the stock will be hot!
If you refrigerate your strained chicken stock overnight, any fat left will rise to the top in a solid form. This makes for easy removal of the fat (just scrape if off with a spoon and discard). The stock becomes jelly-like when it’s chilled. It will return to its normal liquid state once it warms up.
Storing Chicken Stock: The chicken stock can be refrigerated up to 3 day in advance of using. If not planning to use the chicken stock within 3 days, place in the freezer until ready to use. Whether the stock has been refrigerated until cold or stored in the freezer, there will be a thin layer of chicken fat that has congealed on the top. Remove that by scraping it off with a spoon before you cook with the stock. Discard the congealed fat. I usually refrigerate my chicken stock and skim off the fat before using in my soup making.
* I like to use the the Costco rotisserie chickens. They are much cheaper to buy and very delicious and moist. Cut or pull most of the meat off the bones and skin; reserve approximately 50% of the chicken meat for the soup (as much or as little as you desire).
** To extract the most flavor from your stock ingredients, start with cold water.
*** The amount and types of vegetables used in your stock can vary according to your taste. I like to save vegetable scraps (such as vegetable scraps from carrots, celery, kale, zucchini, squash, bell peppers, spinach, onions, beets, beet greens, potato peelings) in a ziplock bag in freezer to add to stock. This adds a lot of additional nutrients.
Homemade Chicken Stock Recipe https://whatscookingamerica.net/Sauces_Condiments/HomemadeChickenStock.htm