I used Purina's Layena crumbles, then switched to Layena pellets. My birds hated them, and refused to eat them. they tried to get everything from free-rangng. I didn't have oyster shell, because Purina Layena was a complete feed. But, this only works if they are eating it. Mine actually starved themselves when faced with only Layena pellets. Shells got thin, and then disappeared, leaving me with shell-less eggs, and at one point in the summer, almost NO eggs. I switched back to crumbles. They started eating, and laying again. But still, if they had had oyster shell free choice through it all, they would not have had the soft-shelled problems. I have one bird who is just now recovering from soft-shell egg-binding peritonitis. This might be a coincidence, but I still wish I had offered free choice oyster shell all along.