Cover chicken with water, and bring to a boil in a large Dutch oven.
Add 1½ teaspoons salt, ½ teaspoon pepper, garlic powder, thyme, and red pepper.
Cover, reduce heat, and simmer 1 hour.
Remove chicken, reserving broth in Dutch oven; cool chicken.
Skim fat from broth, and bring broth to a simmer.
Skin, bone, and coarsely chop chicken.
Add chicken, bouillon granules, and remaining salt and pepper to broth.
Return to simmer.
Combine flour and poultry seasoning in a bowl.
Cut in shortening and bacon drippings with a pastry blender until mixture is crumbly.
Add milk, stirring until dry ingredients are moistened.
Turn dough out onto a lightly floured surface.
Roll out to ⅛-inch thickness; cut into 1-inch pieces.
Bring broth mixture to a boil.
Drop dumplings, a few at a time, into boiling broth, stirring gently.
Reduce heat, cover, and simmer, stirring often, for 25 minutes.
