I've given my 4 week old chicks some grass and a bit of oatmeal, but the pet stores only sell 'shell grit' There is no nutritional information, instructions, only 'Shell grit, fine mix 2KG'... It seems to be made up of little different shells and bits. I'm just wondering, is this safe for my chicks? Because I've been reading about grit and it seems like extra calcium is bad for chicks If this is so, is there a way to make my own grit for them by crushing rocks up? Or should I take them outside everyday for them to pick their own rocks?