My oldest chicks are 3 weeks old and I'm wondering when I should start to give them grit? When I take them outside they eat any lil creepy crawly they can find but ants are their favorite, but now I'm worried cause they don't get grit (didn't know they needed it) I haven't let them go on any more outdoor adventures cause I don't want them eating stuff they can't digest! So when can I give grit?