I don't have the $$ to buy new CDs to hang around, and I don't have any old ones. I cheat. I have LOTS of disposable pie pans in various sizes, from pot pies and frozen pies. They are shiny and work just as well as CDs. If you have a few close together (like a mobile) they make a very annoying noise, but it keeps the wild birds away from my chickens. I have problems with starlings, sparrows and other wild birds. And hawks and owls. So far, haven't lost of my girls to the raptors...