i had this problem afew yr back and tried all of the above apart from the roll away nest box ? i couldnt stop the one that was doing it no matter what i did then i got a visit from old charlie boy with him taking 2 of my hens and then it stopped, he rather had a good word with them and put the shits up em or one of the 2 was the egg eater, only way to stop it is to cull the one thats doing it if you can find which one it is, atb