I have two Ameraucana hens that are 9 1/2 months old. They started laying about 2 months ago. They consistently lay eggs that have lots of calcium on the outside of them. Is this something I should be concerned about? Is it a sign of insufficient calcium, or too much? They eat Purina Flock Raiser Crumbles with oyster shell. I also feed their egg shells back to them (after baking them and grinding them to powder in the blender first). What do you think? None of my other chickens or turkeys have eggs like these.