If you are only feeding pellets or crumbles they don't need grit...but if you are feeding scratch or any whole grains, then they do need it. Chickens gizzards are like grinders. The grit is the stone. The muscles move the grit around to pulverize the solid food. Pellets & crumbles will easily fall apart in the chicken so it doesh't need grit. Whole or part of grans are hard, and the chicken needs the grit to break the hard stuff down so It passes through to the area where it is absorbed. A gizzard will become stronger the longer it has grit in it. So, if you are not feeding anything that is hard, and suddenly feed hard grain, the chicken will have a hard time breaking the grain down. So, one should introduce grains gradually to a chicken that has not had grit before, or has been eating pellets or crumbles. It takes a couple of weeks with the grit for the chicken to get to its strongest point in the gizzard.
Only pellets and crumbles? That just seems cruel. Not to mention boring.
