I took two of my four week old chicks outside today and I watched horrified while one of them pecked up a relatively large rock and ate it before I could stop her. Then, not a minute later, she did it again. The rocks looked like they had some sharp edges and were about 1/4 the size of a pea. This is the first time I've raised chicks and I'm soooo worried about her. I know they need grit, but those seemed like awfully large rocks. Is this normal? Do you think I should be worried about her? Hopefully this is what people mean when they say 'grit'? I have been picturing grit as sand-sized, not pebble-sized..... Thanks to anyone with advice.