They have been laying about 4-5 months. I'll try the All Flock with oyster shell separate, that's a good idea. I've just heard so many people say to feed a layer pellet that I didn't think of anything else.
I have two out of eight hens laying odd eggs consistently every time they lay. One buff Orpington lays eggs coated in a dusty, I'm guessing calcium, film. The eggs literally feel chalky. The other hen, an ISA brown is laying bumpy eggs. All of the eggs even from the normal hens are very tough...