We have processed several meat chickens before. Some of the ones we did today, however seemed to have large, rock hard gizzards (inside - not the crop). At first I thought it was the liver but we think it was the gizzard instead. We usually cage them the night before with only water and haven't had any problems. This time something came up and we couldn't get to them, so we gave them some food for the day and just water that night. Four out of seven of them had very large, very HARD gizzards. Were they ill and if so, would they be ok to eat. They didn't look or act sick.