Had she been in molt? if not then if you clipped enough of her wing she may not have flown away and something may have taken her. did this happen during the day time? we have hawks around here that could probably carry off one of my lighter Muscovy's , also I've lost chickens during daylight hours that were free ranging so preds are around at all hours of the day sorry for your loss. My only chocolate died from laying problems
I honestly don't know if it happened at day I wasn't home.. I think it was probably at day since she my only drake and another hen disappeared at the same time

