Skin the duck breast fillets. Cut up the skin into very small pieces, then cut the duck and chicken flesh into 1cm (¼in) cubes. Mix together the flesh and duck skin, and the pork in a small bowl with the garlic, mace and coriander, orange rind and juice, Cointreau and a generous sprinkling of black pepper. Cover and chill for at least 8 hours.
Put a roasting tin of water in the centre o