These are pretty new layers for us - I mean we've had them almost 9 months but they have just now really started laying regularly. The eggs are beautiful...well formed, bright yellow/orange but their shells are pretty soft. When I crack the eggs, they don't crack into a line but instead they sort of cave in and I have to poke my figures through the inner membrane to get to the yolk. I'm sure it's something I'm not feeding them but I've been feeding all my chickens the same for 5 years - just layer pellet. What can I do to toughen up the shells? I don't feel like I can sell them until I can get them a little stronger.