I am a chicken newbie with a brooder full of assorted bantam chicks. They are just a couple days shy of being a week old. Their bedding is a combination of shredded newspaper and shredded office paper. I have not seen any of them eating the bedding and they have been monitored pretty closely. Their food is medicated chick starter/grower. I haven't given them any treats or anything. They don't have a thermometer in their box, but there is a thermometer in the room and we adjust the heat lamp to make up the difference. They are all noisy and active, they don't act too hot or too cold. All of them are eating and all of them are drinking. Sanitation is good, I clean the feeder and waterer at least daily (with spot checks if I noticed a big poop) and the litter is changed every couple of days. There are about 4 chicks that have swollen crops. They aren't rock hard, but they are tight and round. The chicks are just as active as the others and everyone is eating, drinking and pooping. Following other advise on this site I added apple cider vinegar to their water and I've given them a few drops of olive oil (boy do they hate that). Is there anything else I should be doing? Should I separate these chicks away from the food until the swelling goes down? How often should I give them the oil? I've been putting a small drop on the end of their beaks (making sure it doesn't get near their nose). A few of the chicks (with and without crop issues) have had little pasty butt, which I have cleaned with a warm moist towel.