2.Combine breadcrumbs, herbs, lemon rind, juice and egg in a bowl. Season and mix well. Push into cavity of chicken, securing legs together with string.
3.Combine butter and garlic. Carefully separate skin from breast meat of chicken fillets. Push garlic butter under skin.
4.Rub oil all over skin and sprinkle with salt and pepper to taste.
5.Place chicken on a rack in a baking dish. Scatter potato around chicken. Roast for 1 1/4 hours, turning potato once, until chicken juices run clear when a skewer is inserted into thickest joint, and potato is tender.