I have 6 ducks (3 Pekin, 2 cayugas and 1 runner). The pen has a 6 foot chain link fence around it, open on the top. Its on the edge of a patch of woods, so its always shaded by large pint trees. I let the ducks into the pen this morning at 9 am left for 30 min and when i came back the runner was gone. No trace of him anywhere. The other ducks were out in the pen acting completely normal. I looked all over and no trace of him. Any ideas? Hawk? Raccoon during the day? Its weird. None of the ducks have ever flied out either. He was the best duck too.