Almost a week ago, I took my 3 y/o hen to the vet after pulling an empty, deflated egg from her vet. The vet said she was acting healthy and there was no egg shell left inside her, but gave me some calcium powder and antibiotic in case of egg yolk peritonitis. Everything has been fine, but yesterday she threw up a little bit of water. Still she was acting normally and eating just fine, so I thought maybe she had been drinking too much water because it was so hot out and made herself sick. Her poo has also been watery for a while, as have my other chickens, due to the heat. This evening, however, my hen had been keeping her tail down and standing with her wings slightly out at her sides. When I picked her up to give her the antibiotics tonight she gurgled and threw up water (it wasn't sticky and didn't smell that I could tell). Her vent was clean, crop full, eyes clear, and abdomen soft. However, when I tried to give her a treat tonight after examining her she wouldn't eat. Did she just drink too much water? What are the signs of peritonitis? Thank you for your help.