My longhorn will not lay anymore! Shes almost 2 and she used to lay for me daily. Over the winter her shells got easily thin and I started giving them oyster shells, but she still won't lay and when she does (only once every two weeks) they are so thin and broken. They free range for a couple hours a day, and then are locked in there run and coop because I have neighbor dogs I have to keep an eye on them. Any suggestions?