My chickens won't accept straw into their nests. I want straw in there to make the nesting box cleaner, and to protect against accidental breakage. Used to be that my hens would make a nest in the straw. Now they kick it all out and just lay in the box. What happened? Got any tips on what to do or alternative nesting materials? I have tried straw, hay, excelsior, (I know I didn't spell that right. But it is shredded aspin bark we used to use at work to make swamp cooler pads). They won't have any of it. My boxes look like crap and they are hard to keep clean.