Remember that in most cases, your flock is getting gravel and such on their own as they scratch at the ground. The type of rock will vary depending on where you live in the world. Chickens pick up grit whilst foraging, which is kept for a while in the gizzard to perform this grinding process. Most chickens love grit and will eat as much as you offer. If your chickens are kept truly free range then they will find enough of this on their own but these days, few of us have the space or the security from predators to be able to allow them to do this naturally. It's not a problem if there are still big pieces in there, the chicks will pick out the size they need. Make a Chicken Brooder Out of Cardboard Boxes An easy-to-make chicken brooder for growing chicks has a few other benefits, too. If the chickens are free ranging they will usually find enough grit on their own Honesty it's probably not worth the effort to make your own since it's not very expensive to buy it Most "store bought" grit is pulverized granite.. so you would have to find granite and then a way to crush it If possible, get granite because it is long lasting. Make sure the mix you're buying for young chickens - up to 18 weeks old - does not have added calcium. Sand is usually too fine and doesn't have enough rough edges to serve as grit for chickens. ... Live The Good Life with GRIT! Chicken grit is available for purchase at feed stores. Whereas all chickens need grit, added calcium is needed only for laying hens and can be detrimental for young chicks or pullets - it damages the kidneys. I use regular chicken grit but pound it up a little with a mortar and pestle. Start chicks on grit once they leave the brooder and are introduced to outside forage and feed sources that are not solely a pellet or crumble (grass, greens, bugs) and/or once you start feeding scratch or any grains. The chickens will take what they need. The grit is a mix of two particle sizes, so it works for smaller birds and standard breeds. ... Raising chickens is not a new phenomenon, nor does it need to be difficult. When to Start Grit for Chickens.