I just had a beautiful americana die in my arms. She was about 3 years old. The only symptoms started about 3 days ago. They were lethargic-but not too much, she'd still go out and graze. I was able to pick her up yesterday & looked her over. Her crop was airy with a few seeds I could feel. I gently massaged it and clear liquid came out. I gave her AVC in her water. She didn't eat anything. Today, she was hiding in the coop. I picked her up to check her & still the same with her crop. This time the liquid was not clear, just slightly yellow. She seemed to be gasping for air. I gently massaged her crop-no burps or smelly liquid like I have experienced in the past with other chickens that had sour crop. She just acted like she couldn't breath. I put her on the ground, she flipped over-shook a little & died. Mucusy poo came out, along with the rest of the liquid from her crop. What the heck happened? She hadn't lost weight. I have lost 3 chickens in the last 3-4 months with sour crop. They eat layer feed, minimal scratch grain as a treat. AVC in their water. I have treated them with oxytetracycline last week-trying to save another chicken with sour crop-didn't work. Any ideas? Why do I keep having chickens with sour crop? No one is laying right now. What to do?