Canning Broth for the winter

When putting up broth for the winter, its nice to do as much as you can at one time given the time investment of pressure canning. For us, we use an enormous old Army cooking pot (probably 5-8 gallons or more) and cook it on a turkey fryer outside. Cook and store on day 1 and can on day 2. Day 1. Fill you big pot half to 3/4 full with water, add chicken backs. For 5 gallons + we use about 10 backs. Add a large bag of carrots, a whole bag of celery and cut up 6-8 onions. Add seasoning and about 3/4 cup of salt. Bring to a boil. Simmer for 2 hours. Strain the broth, separating the broth from the veggies and backs. Keep the backs, debone later - there is a lot of meat there.  Discard veggies. Let broth cool and move into a refrigerator or outdoor cooler. Day 2: skim as much of the fat off as possible. Bring back to a boil, reduce back to simmer and start the canning process.