Prolonged survival of skin allografts in mallards

Skin allografts were exchanged between 25 males and 25 female mallards (Anas platyrhynchos) within 2 days after hatching. Of the 42 ducks that survived and whose grafts healed, 14% rejected rapidly before the grafts became feathered, 20% rejected between 3-6 weeks, and one duck rejected when he was 10 weeks old. Twenty-seven of the 42 ducks (64%) retained their grafts for at least 5 months. The results demonstrate that, in mallards, neither inbreeding nor any treatment of the host is necessary for prolonged survival of skin allografts made shortly after hatching.