I recently just checked her wing and there’s a blood stain on it, I don’t know if this is bad so please tell me what to do because idk if it’s hurting her?
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
You should wash it up with a baby wipe or a paper towel with water, and try to identify if it was a scratch on the skin, or a broke feather shaft. Also, if you have any
blu-kote to put on it. This has happened to me too.