She's almost a year old Buff Orpington who used to be a really good egg layer - solid shell, nice size egg and never had trouble with egg laying before. About 2 months ago, suddenly she stopped laying for about a little over a week. During that time, her diet hadn't changed. I always have oyster shell and grits freely accessible to the chickens and give them nuts, black oil sunflower seeds, dried worms, etc. as treats. So after stop laying for more than a week, she laid two "fart eggs". Then it took her over a week or so to lay a normal egg again. I was thrilled.... Then suddenly, about 10 days or so now, she has been laying soft shell egg almost every other day. In between these days that she laid soft shell eggs, she laid several normal eggs. There was a day when she laid a normal egg in the morning, then around midnight, she laid a soft shell. Yesterday she did not lay, and now I came home, another soft shell egg. To make matter worse, she had already picked up a habit of eating these soft shell eggs and had taught another chicken how to eat it as well.
I am feeding her Purina Layer, and a separate container for grit and oyster shell. For treats, I still give them nuts, dried worms, grapes, a little bit of organic yogurt. The last 2 weeks we have had good rain here so for a few days I started digging earth worms and gave them some. They hadn't had earth worms for several days now.
I am really worry and I don't know what else to do.