Straw bales make such an excellent wind barrier, they build houses out of them. Cheap and long lasting.
Here's another vote for a straw bale. I've got a step-up coop and I got a bale to use as a step to get in there. A year later it's still intact and stable. I can feel low spots and soft spots. I'm gonna have to invest another $7 any day now. But I can't believe how that thing's held up!
When I have to replace it I'll spread it in the nesting boxes and run as bedding or add some of it to the compost pile. Some people even gouge out a hole and plant in them!