I am not sure if they carry feather decor, but I have heard great things about Golden State Flowers on South Blvd. It does not look pretty from the outside but I have been told that they have tons of wedding supplies and decorations at great prices. It might be worth it to give them and call and check on feathers. Good luck!
Garden Ridge may have feathers. I would also check out ebay. I know that one of my friends bought some feathers on there for cheap.
http://www.save-on-crafts.com/purpleostrich.html This site has great feathers. We used them recently at a baby shower and posted the photos on FaceBook here: http://www.facebook.com/pages/1812-Hitching-Post/54152377817
Click on each tool to see a sample.