I've used electronic ultrasonic pest repellent devices in the past with success. This is one option you have. I use to place them around the feed storage barn back when we had large herds of cattle.
I'm not sure if it's a good idea around chickens or not though.
http://www.ehow.com/about_5240763_do-machines-work-repel-rodents_.html
I'm not sure if it's a good idea around chickens or not though.
http://www.ehow.com/about_5240763_do-machines-work-repel-rodents_.html