In a turducken, duck is stuffed between the chicken and turkey.
The name itself is a compact clue: “tur” comes from turkey, “duck” from duck, and “en” from chicken. In the standard arrangement, a deboned chicken goes inside a deboned duck, which then goes inside a deboned turkey. Stuffing or sausage may fill the gaps between the birds.
Turducken is associated especially with Louisiana and Cajun cooking. Its modern popularity grew through chef Paul Prudhomme and television commentator John Madden, who famously promoted it during NFL broadcasts. Madden first ate one on air in 1996.
A common mix-up is the direction of the layers. The duck is not outside the turkey, and the chicken is not between the turkey and duck in a separate recipe: chicken is the innermost bird, duck is in the middle, and turkey forms the outer layer. Gooducken is a related English variation that uses goose instead of turkey.