I live in lake country, so we typically just use beach sand instead of #1 grit. For people living in the city, they can also buy playground sand by the bag from the big box stores, which is about the same thing as #1 grit.
If none of that is available, you could get a shovel full of dirt and put some of that in for the chicks. Just make sure it is not from a place where people spray the lawn/property with chemicals and it should be OK. I started putting in clumps of dirt with grass in the brooder to get my chicks ready to go out into the big coop with the chicken run. Even the little chicks know enough to scratch it apart, look for bugs, and eat some grit.