One of my hens laid a very small egg recently. She is half White Leghorn and half Buff Orpington, I would guess, and her regular eggs are white shelled and large. She is almost 2 1/2 years old and has been a good layer. Since laying the small egg she has not laid another. I am getting worried because she usually lays every day or every other day. What do you think it could be? I read that stress can cause this, but I'm wondering whether she could have ovarian cancer or something? She seems healthy and happy. Could it be mites? None of the others seem affected, and my 4 year old Barred Rock is laying well, and so is the Silver-Laced Sebright Bantam.