Our third adult bird died this morning. They present with swollen yes, lethargy and tail down. We thought it was sour crop. Separated them from the flock, Tried to massage the crop, the birds open their mouths like they want to throw up, they are thirsty and have bad breath. I am taking the dead birds to the agricultural center tomorrow for an autopsy, but would welcome any advice. I attached a photo of the bird that just died a few minutes ago. She showed symptoms just this morning! Thank you fellow chicken farmers.