I brought my chicken with a similar problem to the vet yesterday. I'm not sure if this will be useful to you, but I thought I would share. On Wed. morning I separated the chicken and put her on a water only diet. I figured if she was still pooping, then something in her crop was getting through. Later that day I took her to the vet. Because she had not eaten all day, her crop was a little smaller. The vet tried to flush out her crop and got out some grass, grit, etc. But she could not flush out a grape sized mass. The vet feels that because the mass moves around in her crop, it is likely causing a partial blockage, thus causing her huge crop. So, she is to remain separated for now. I have put apple cider vinegar in her water. I have been watering down some starter mash and feeding her about 1tbs a few times a day. The hope is that the vinegar and massage will help break down the mass so it can pass through (as long as it is something organic). I'm not sure what to do if is doesn't pass. The vet bill was pricey and the next step is to give her anethesia and try to pull it out with a hook. I'm not sure what we will do in that case. I'll keep my fingers crossed that it goes away and that her crop shrinks back to normal size. Hope this was helpful to you. How is your chicken doing?