Add chicken breasts to the bottom of a three quart crock pot. Whisk together onion soup mix, chicken soup, chicken broth, water, black pepper, flour, garlic powder and poultry seasoning in a bowl until all ingredients are well combined and mixture is smooth. Pour over chicken breasts in crock pot.
Cook on low for 6 to 7 hours or high for 4 to 5 hours or until chicken is done. Removed chicken from pot, shred with a fork and add back to the gravy.
Notes
I did not add salt to this recipe since the onion soup mix and the canned chicken soup both have salt. You can add more if you like.