Add several quarts of water, fat, salt, black pepper, and crushed red pepper to a large stockpot and bring to a boil.

Chicken should be chopped up and covered with water. When the chicken is cooked and coming off the bones, bring the pot back to a boil and simmer it for one to two hours.

Chicken should be removed from soup and strained into a big bowl with any stock remaining.

After the chicken has cooled, remove the meat from the bones and discard the skin and bones. Use your hands to rip the chicken into little pieces. Take care to get rid of every bone.

To get rid of the chicken residue that has adhered to the pot's sides, wash the cooking pot after straining and transferring the broth to a different pan or bowl. Refill the pot with the broth.

Add the chosen chicken to the saucepan and turn the heat to simmer when the stock returns to a boil.

Add two sleeves of crushed saltines gradually to the saucepan. Stir while simmering continues. There shouldn't be a lot of extra liquid in the mull. More crackers should be added if there is liquid.

Stir often while simmering on low heat for about 20 minutes, or until heated and thickened—hence the name Mull.

The red pepper has a chance to be heard, therefore the next day is better.