I just wanted to post my experiences as we just lost a chicken to being egg bound and we have the results from the vet who did a mini autopsy.
So about a week ago we noticed our Rhode Island Red named Lucy had poop stuck on her rear feathers. I didn't think too much of it,although I did look closer to make sure she didn't have any sores or wounds. Three days ago we noticed she wasn't in the coop at night when we closed it. We found her off on her own just standing. We picked her up and put her in her nesting box but she just stood. The next day we checked her and she was still standing and didn't eat anything even though we put food/water right in front of her. I noticed even more compacted droppings on her. So we took her inside (its become pretty cold here) and I cut off the bad feathers and we gave her a good warm bath. It seemed to help. But at that point I didn't see anything that looked like lice, mites, worms, sore, or really anything other than dirty rear end feathers. I read Backyard Chicken and started to think it had something to do with an egg not coming out. I felt her abdomen and it did feel hard. I put some vaseline on her vent but really didn't know what else to do as we had already done the warm water bath. She did eat some yesterday and her poop was running and all white.
This morning she was very lethargic and didn't want to eat anything. I could tell it was the end as her breathing was getting heavy, so we called the vet and made an appointment. She died just before the appointment but we took her in and they did a animal autopsy kind of inspection (a necro-something). When I spoke ot the vet she said she could see an ovaduct (sp?) rupture and there were literally yolks in her abdomen surrounding her organs. She also did have one large egg that hadn't come out. Her organs were enlarged mainly due to inflammation caused by the yolks/liquids in her belly.
Lucy was apparently older than were were told she was. She hadn't been laying for most of the year but only recently started again. Te vet had seen it before where the reproductive system was dormant for a while, then goes haywire and things similar to this happen (ruptures). The vet seemed to say that its awfully hard to know when a chicken is sick until its too late and there's often very little that can be done.
I just wanted to tell our story because this site has been SO helpful to me. Reading other peoples experiences have really helped me. My family raised chickens when I was a kid but they weren't pets... now my chickens are pets and dealing with them dying is so much harder. Having this site has been a Godsend!