indoor chicks I toss in a handful of grit and a handful of finch seed on top of it so they ingest the grit accidentally. after the first couple times of that i give grit in a bowl
once outside they don't need it except winter
sand will work I think for chicks. I wanted to make sure so bought the bag of grit. It was cheap enough and at 1 handful every few days will last a long time
if they are eating ANYTHING other than chick starter mash they must have grit
I bought a bag of chick grit for $4 at tractor supply and put out a handful every couple days along with finch seed as treat for my 1.5 week old chicks