I noticed that one of my 12 week old hens has a lump on the right side of her neck. It is hard and feels about the size of a large marble. She is eating, drinking, and running around like the other chicks. I have researched on this site and it sounds similar to an impacted crop...but I don't think it is in the right place. It is very hard, as well. It almost looks like she has scoliosis in her neck and the vertibrae is poking out. Should I assume it's the crop and treat her with mineral oil? The lump is on her neck not on her breast area. Thanks for your help.