I have been putting our 6 week old chicks out in the portable run each day, but most of our yard is sandy or clay so not much grass. We also have a lot of wild onion growing. Today, I put the run in a grassy spot, and the chicks went crazy with the grass. I put their food and water in the run as well, and threw in some chick grit, since this patch didn't have visible sand. Can they eat too much? I have heard of them getting crop impaction from eating long grass. I know it is probably a silly question since most chicks that are hen brooded just eat grass from the start, but I am completely new at this and am wondering if there is anything else I need to do to make sure they don't get impacted, other than offer grit.