I picked up a few cheap solar spot lights on sale at the hardware store to day and it got me thinking
If I got some adhesive reflective tape, the red and white kind http://www.harborfreight.com/10-piece-reflective-tape-97562.html
and cut it into eye shapes and stuck it on to surfaces around the chicken yard and pointed the spot light at it from a distance that might simulate eyes of a predator looking back. Might give real predators a reason to avoid the area, especially if I made it portable and could move it around the yard easily. You could even cut them different sizes and group them together some red some white to give the illusion of depth and create "pack".
Could be a fun cheap project to fool around with.