several whole peppercorns(or about 1/2 teaspoon ground pepper)
2-3tops of celery stalks(or the stalk, itself)
1-2large carrots, cut in half
1whole onion, unpeeled and quartered
Place the raw chicken breasts into a very large stock pot (no smaller than an 8-quart pot). Cover with cold water, then add the rest of the ingredients to the pot. Bring to a boil over high heat. Once boiling, lower the heat and allow to cook at a gentle boil for at least 1 1/2 hours (the longer, the better).
Use a large slotted spoon to remove the cooked chicken breasts from the pot and transfer to a large platter. Cover loosely with foil and let rest for 20 minutes. Use forks or tongs to shred the meat, discarding the skin, bones and fat. Use the chicken immediately in your recipe. Store unused shredded chicken in a sealed tight container in the fridge for a few days, or in a freezer bag in the freezer for up to two months.
After removing the chicken breasts from the pot, pour the remaining ingredients through a mesh strainer and into a large bowl or two, to reserve the broth. Discard the vegetables and store the broth in the fridge for up to 3 days, or freeze for later use. I recommend to freeze the broth in 2-cup portions then use later in soups, rice, sauces, etc.
Freeze any extra vegetables and their scraps to throw into the pot when you're ready to boil up some chicken and broth! When ready to use the broth, skim the solidified fat from the top.