Mareloo, if you get the builders sand, it would be a good idea to wash it real good just in case it has contaminants. Sand for children's sandboxes is already cleaned (and screened), you can use this right away--do you have a Lowe's or WalMart nearby?
I've given my week-old chicks tender blades of grass to eat. No problem, just make sure it isn't sprayed. They also entertained themselves with the grass, playing "keep-away" and you will have lots of fun watching them. Did you see the Treats Chart?