Hi All, A newbie here. My amazing 5 week old chickens- Blossom, Pedro, Frango, & Destructo ( I did not name them...lol) are ready for treats other than Mealy worms. Do I need to buy them chicken grit if their coop is already on top of a dirt? I have some sand that I used for gardening. Would that work if I just spread it on the ground?