Not likely any pain. The feather shafts do contain blood vessels, so it is possible that duck slightly cracked feather a little too far up shaft. Injury can have come from scraping on a sharp point of fencing, or wire. I would not worry too much about it, and if you wish, then wash it clean. I don't have ducks, but I know chickens are attracted to wounds on other chickens, and will peck that chicken. Sometimes viciously.
WISHING YOU BEST,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,and
