In a large resealable plastic bag, combine chicken, buttermilk and salt. Refrigerate for 8 hours or overnight. Heat oil in deep-fryer to 375 degrees F (190 degrees C). In a large resealable plastic bag, combine flour, Italian dressing mix, poultry seasoning, salt and pepper. Remove chicken from buttermilk, and coat well with flour mixture. Let set on a plate for about 10 minutes. Fry in hot oil until meat is no longer pink, and breading is golden brown, about 20 minutes. Drain on paper towels.