Esther, are you sure it was a virus? We lost a couple of chucks for what seemed like unexplained reasons. It was only recently that we noticed that our last brown hen looked a bit dull and not moving, that her crop was sticking out. Well Mike noticed her crop, not me. But her comb had also gone a bit shriveled and purpley coloured. She was fine only hours before! This is what happened to the others we lost. Anyhow, we syringed some olive oil down her neck and massaged it for 10/15 mins and repeated this next morning, lunchtime and evening. She was a different bird the next day. I'm not 100% sure if that's what our other two had but might be worth checking their crops aren't hard?