We have one hen that refuses to get off the eggs. The problem? Well, Sparta is in the dog kennel, so the eggs have zero chance of fertilization. Go figure. It's the perfect time to let her sit on some, but we can't. Sparta has a lot of healing to do first.
Last year I tied pie pans to recycled metal tent poles, and placed them in the strawberry beds. When the wind blows, they bang and scare off the birds. I know it's kind of "hill billy" but it works.
This spring I reset three of them, and I noticed it even keeps the hens out of them (if there is wind). I may have to add a few more to my herb garden too (or fence the chickens near the barn).