Place chicken bones, chopped onion, celery and carrot in a large pot. Cover with water, adding a little more if needed. Add the peppercorns and salt, bring to a simmer.

Skim any "foam" that rises to the surface and discard. Simmer for 1 1/2 hours. Strain and use the clear liquid, discarding the bones and vegetables.

If time permits, refrigerate the broth overnight and remove any fat that solidifies on top. Can be frozen for later use.