My four chicks are coming onto 4 weeks old, brooded inside. All going well so far! Once we've completed construction on the new run extension (2-3 weeks from now?) plans are to transition the girls into the existing run, which has a raised coop. Both existing run and extension run (they'll eventually become one space) are on coarse sand--think horse turnout pens. Is there a preferred way to introduce chicks to this sand material prior to when they make The Big Move to their new permanent space? Should I bring a bit of the sand material into their brooder pen now? Someone posted about their chicks ingesting excessive amounts of grit, so I'm wondering about this. The material is not grit, although it is coarse, but not beach sand. Our barn driveway is, however, washed granite gravel, which my older hens use as their grit source. Thoughts? Thanks.