That's usually a sign of eating well. food is STORED in the crop before it is digested. if the chick has access to feed 24/7 it's likely the crop will be very full at night, empty in the morning and they usually eat quite early so likely full again . if your worried the crop is impacted you can remove the food in the pm. and check in the am to make sure it emptied. I like seeing my girls with a full crop. it means they are eating well. it's usually only empty in early am after a nights sleep. They usually feed during the day. Remember whatever they eat goes into the crop then gets digested from there. the gizzard "chews" the food then it gets digested. you can look online and see how different chickens bodies work from ours. we have two lungs they have more, the food goes to the crop then through there system. it's really interesting. you ought to check it out online.