METHOD

1. Preheat oven to 200°C (400°F). Place the butter, garlic and lemon rind in a small bowl and mix to combine. Carefully loosen the skin of the chicken at the breast with your fingers. Push the butter mixture under the skin. Tie the legs together with kitchen string and set aside. 
2. Heat the oil in a large heavy-based ovenproof saucepan over medium heat. Add the onion, carrot and celery and cook for 8 minutes or until softened. Add the salt, pepper, barley and stock and stir to combine. Add the chicken, breast-side-up, bring to a simmer and cover with a tight-fitting lid. Transfer to the oven and cook for 1 hour. Remove the chicken from the pan and set aside to cool for 10 minutes. Cover the barley mixture and set aside. Remove and discard the skin from the chicken. Shred the meat and stir into the barley mixture with the tarragon. 
3. Increase the oven temperature to 220°C (425°F). Lightly grease 2 x 16cm (625ml) round pie dishes. Using 1 sheet of the pastry, line the dishes and trim the edges. Fill with the chicken mixture. Cut the remaining pastry sheet into 30 x 2cm-wide strips.
4. Brush the pie edges with egg and top with the strips, overlapping to create a lattice pattern. Trim, press the edges and brush the lattice with egg. Place the pies on an oven tray and cook for 15 minutes. Reduce the oven temperature to 180°C (350°F) and bake for a further 15 minutes or until golden. Serve.  Serves 8