One of our girls, every 10 to 14 days seems to lay an egg with no shell. We had seen small messes in a nesting box--maybe what looks like a few tablespoons of an egg but not yellow. We thought perhaps we had an egg eater but there were NO trace of shells at all. Tonight we let them out to free range and our 19 month Orpington stopped and discharged what looked like just an egg white. About 3 minutes later she discharged a nicely formed yolk. Any ideas??