Grit for Digestion?

[ricachica]

My chickens are cooped up...no free range. What do I need to provide for their digestion they would normally get through digesting grit from the ground? I heard I need to purchase some stuff for them to eat, like gravel. What is it? Would sand work? I feed them back their shells. Is that enough? I have some gravel used to spread over the lawn called Pelletized Dolomite Lime that is a source of magnesium and calcium. It is not feed grade, but can they eat that or is that unsafe for animals?

 

[Kikiriki]

Sand is okay, but it is often very polished and very similar in size. At the feed store I just bought a bag of grit. It is granite that is varied in size and not polished. i put it in with their food once a week, and they eat what they want and leave the rest. I dont dump it out of the feeder, just leave it for the next day because they typically finish almost all their food. I bring it in the house overnight. By the end of the week they have eaten it all. I give about 1/3 cup each week. They have daily access to sand here.

I am not sure on the lime. Dont give it to them until you research that. It makes a big difference what type it is!