So 2 of my black sex links are laying eggs without a problem. But the barred rock is having issues. The egg breaks as soon as it's pushed out from the drop. Idk what to do. The bottom of the nest box is plywood and we have pine shavings in there. They end up pushing all the shavings out of the way where they lay so they egg drops on straight plywood. Is there something else I could put in the box to help?