Place the chicken into a large stockpot.

Add the onion, carrots, celery, bay leaf, and peppercorns to the pot.

Cover the chicken and vegetables with 10-16 cups of water.

Bring the mixture to a boil, then reduce heat to low and simmer for 1.5 - 2 hours, or until the chicken is fully cooked.

Remove the chicken from the pot and let it cool slightly. Shred the meat and set aside.

Strain the broth through a fine-mesh sieve to remove the vegetables and peppercorns.

Let the broth cool completely before storing in airtight containers in the refrigerator or freezer.