I recently put lime down to help control the bad smell when the chicken pen turns to muck during heavy rains. It's a combination of chicken poop, wet food, and decaying vegetation. So I put a thick coat of crushed "barn lime" on the ground, and covered that with hay (NOT straw like I made the mistake of doing last time), and then a good thick layer of pine shavings. I knew the chickens had to be out of the pen to put the lime down, because it's pure dust, and inhaling too much of it can be bad for almost any animal. So they had to be out until it was put down and the dust had settled. But what about EATING it? I sometimes use lime in my fish tanks to pull the PH back where I actually want it. And lime is essentially the "calcium" supplement they put in daily multi-vitamin pills they sell at drug stores. So what about having chickens EAT it? I have a huge amount leftover, and the "ingredient" is calcium carbonate. Isn't that what chickens use to actually produce the egg shells when it's passing through the oviduct? I know I don't need to give it to them all at once, or in large amounts. I know they need a well-rounded diet. And I don't have any problems with my flock having shell-less eggs, so I would REALLY have to thin it out more than other people who do have those issues. But would it be fine to mix a few spoonfuls into a bucket of feed when feeding my adult chickens?