I use plastic totes with a hole cut in one end for nest boxes. I put shavings inside. All the hens use these except for one group. I have a White Marans roosters with some black hens split for white. These hens are laying beautiful dark eggs. But they won't use the nest box. They lay on the ground and almost all the eggs are too dirty for hatching. Moreover, when I put shavings in the nest box, they immediately kick all the shavings out. What's up with these birds? I need those eggs to be clean!