I did a search, but am not finding a definitive answer. I have found three of these things in the run this last week- it looks like an egg shaped thick membrane- torn up and empty - I think the chickens have scratched them open, but they are not sticky and there does not appear to be yolk residue. I have 8 young pullets who have just started laying. They get oyster shell mixed with some scratch several days a week as a treat- and they are on Purina Layena. Do I need to keep oyster shell out constantly? Will this clear up, or do I need to figure out who is doing it and worry?