We have ten hens in a coop and a large fenced run. They have plenty of room, plenty of food/water and crushed oyster shell. They were all purchased as baby chicks (Red Sex Links) this spring and have all been laying for probably three months. I believe that it's just one hen but almost every day, I get an egg with about a 1/8th inch square hole in the blunt end of the shell. The shell looks like it was completely formed but then the hole got "punched" in because the shell is still there. If I crack the egg, the membrane inside covers the hole but I still toss the egg. I've added more shavings to the laying boxes just to be sure she wasn't shooting the egg out to hard and it was hitting the wooden floor but I don't see how that could possibly be happening, for sure now that there's a deep layer of shavings. Any ideas as to why this is happening? Thanks!