First you need to make a whole chicken in the slow cooker - such as
Easy Slow Cooker Whole Chicken Recipe
Once you cooked the whole chicken leave the juices and bones in the slow cooker - I use a 4 quart. Fill the slow cooker with water cover and cook the "broth" for about 10 hours. If you have extra veggies around you can put that in the slow cooker as well for extra flavor.
Strain the liquid from the bones and scraps. I use a colander first. Next I use a clean kitchen towel - this really helps make a "clean broth"
Next pour 2 cups of broth ( or whatever measurement amount you want) into Ziploc bags or Tupperware and place your homemade broth in the freezer. I usually taste my broth first - it usually needs a little salt
Whenever you need broth just defrost a pack of broth. I would recommend using up your homemade broth within 6 months of freezing.
Enjoy!
Recipe by Budget Savvy Diva at https://www.budgetsavvydiva.com/2013/02/chicken-broth-recipe/