My black Sex Link started to develop a large crop about a year and a half ago. Her crop worked and would empty itself for a long time. Then she started to stumble and have difficulty getting around and eating.
She appeared to be increasingly uncomfortable, and was no longer leaving the coop. On her last night, she couldn't roost, so we decided to put her down, sadly.
This video was taken a few weeks ago when she was able to get around.
We dispatched her with a single shot from a .22, which worked extremely well. She didn't know a thing. I was worried about disease because she was displaying neurological signs, and her crop had grown SO large that my veterinarian feared it was actually a mass.
Necropsy shows that the mass was, indeed, a very, very large and nonfunctional crop. I also dissected out the nerves in her legs and found them and everything else in there to be normal. She was in surprisingly good weight, actually, considering. She was a little thin and had very little belly fat, but not too bad overall. I suspect the stumbling was due to her static crop and the grain alcohol she was manufacturing in there--I mean, she was probably drunk all the time.
I thought it was interesting enough to share. I read a little about pendulous crop when I first noticed her problem, and from what I can glean, it is a genetic predisposition.