I'm wondering people's opinions on the best choice of feed for a mixed flock of pre-lay pullets, adult hens and roosters, and sometimes the free range guineas will eat this too. I want to change my feed, they all eat layer crumbles now. I'm concerned about the amount of calcium in the layer feed for the roos and young birds. My end goal is to switch them soon and offer free choice oyster shells. I would like to know what you feed and what type of flock you have. Also does anyone know the acceptable range of calcium that I shoykd be looking for on the feed bag labels?