Complex sentence: She also has the gift her grandmother calls the "confidence of horses," which allows Corrie to communicate with her horse, Thunder Jam (TJ), who lives dispiritedly in his sire's shadow.
Split into simpler sentences: She also has the gift her grandmother calls the "confidence of horses". It allows Corrie to communicate with her horse, Thunder Jam (TJ), who lives dispiritedly in his sire's shadow.