this morning I saw one of 16 duckling eaten. the other 15 looked fine. it was in an enclosed area with nettings on top. no signs of digging. there are a few gaps here and there. all my adult chickens and ducks are fine (not in the enclosure with the ducklings). the body is all gone. one head + 1-2 inches of neck left. what could have done this? i will move them to more secured enclosure at night. i keep the adults in the pen and run for a long time and did not have an issue before.