Nothing - it's a coincidence.
I have heard that feathers represent those who have left this earth, as a reminder they are still around to watch over us.
When you find a crow feather, it represents good health and staying away from harsh cancers and diseases.
There was/is a cardinal nearby
There are Angels in your life
The blue feather is what you use to purpose to the person you like when they have a red heart.
It means a bird was just flying by and dropped a feather no omen no sign just simple as that :)
it means you will have good luvck for 100 days
it means its bad luck.
The death of your loved one is ambiguois
Finding a cardinal's feather has no significance other that the pleasure of finding such a pretty thing. There is nothing supernatural involved.
It means a blackbird was in the area.
It means you have a hole in your pillow or quilt.
It means that somewhere in your vicinity a fowl with white feathers lurks.