Welcome to BYC. It could be the crop, but a leaking air sac may also be the problem from trauma during hatch. I'm not sure about this, but perhaps the crop could be full of air, too. I would be reluctant to try deflating the air, so I would just watch it, and I hope the chick makes it.
The crop is very noticeable on chicks in the upper right chest. Subcutaneous emphysema (leaking air sac, windpuff) is a condition where an air sac is injured, and air collects under theskin. If severe, this can cause difficulty breathing, a clicking sound with breathing, or even death. It can be...
This is chick grit available at most farm stores and TSC and when they are older, you can get regular chicken grit, but if they free range they should get some grit in normal ranging: http://media.tractorsupply.com/is/image/TractorSupplyCompany/1014702?$prod_det$
Chick grit is necessary when feeding things other than chick feed, but not necessary if they only eat chicken crumbles until they get outside on the ground.
A full crop is very normal for a chick, and they eat 24 hours a day. I just wanted to make sure your were talking about a normal crop, and not an injury to the chest causing a leaky air sac. Sometimes they can look similar.
Welcome to BYC. Make sure that it's not the chicken's crop that is on the upper right side of it's chest--it will be full after a big meal, then go down. Sometimes chicks can get injured and get a leaking air sac called subcutaneous emphysema under the skin. If it is air, you can stick an 18...