Let me preface by saying... I'm new to chicken keeping. I have about 5 silkies, varying in ages. One of the younger ones (about 4 months old) has a very large crop which is not hard, kind of puffy feeling. This particular lady already went through crook neck when she was about a month old. I followed some remedy advice and she got over that pretty quickly. But now this, and I'm not sure what to make of it. She drinks and eats, but is not as active as the other chickens and will actually sit in a corner of the coop by herself all day instead of joining in with the others. She did go outside for a little bit today and ate some grass. Any suggestions?