Cut the chicken into its respective parts, discarding the carcass.
Pour the buttermilk and egg in a large bowl and whisk well, then place the chicken in the bowl and toss to coat. Cover the bowl with plastic wrap and soak for at least 30 minutes. You can marinate the chicken in this mixture overnight in the refrigerator, if desired.
When ready to fry, combine the flour with the seasonings in a separate large bowl.
Preheat oven to 175°F. Line a baking sheet with aluminum foil and set an oven-safe wire rack on top of the baking sheet; set aside.
In a deep fryer or large Dutch oven set over medium-high heat, heat about 3 inches of vegetable oil to 350°F.
Remove a piece of chicken from the buttermilk, shaking off any excess liquid. Press the piece of chicken into and through the flour mixture, adhering the mixture to all sides. Shake off excess flour and carefully drop the chicken into the hot oil immediately. Repeat with more pieces, frying no more than 3-4 at a time depending on size.
Fry the chicken for 12-15 minutes, turning halfway through, until golden brown.
Remove the chicken from the oil and place it on the wire rack. Place the baking sheet in the oven.
Once the oil returns to 350°F, repeat the dredging and frying process with the remaining pieces of chicken.
When all the chicken is fried, keep them in the oven for about 10-15 minutes, maintaining the internal temperature of 165°F until ready to serve.