was this a sour/ impacted crop or something else

My 10 month old Brahma hen was in excellent health, free ranging and having pellets, she had been wormed two weeks previously. I noticed one afternoon that she was just standing in the garden and generally not right, she did a a watery poop with no solids just white urates Next morning I felt her crop it was very full but was moveable with no single mass. I suspected an impacted crop. I gave her olive oil with a syringe carefully onto her tongue, letting her swallow and gently massaged the crop. Nothing changed over the day, more watery poop. I am a novice and got very worried. Late afternoon took her to the vet. No clinical signs of any other problem other than comb a very dark red. She was open mouth breathing- ?stress/heat. Crop still large but you coukd clearly feel and move food around, more watery poop. Vet gave a painkiller and antibiotics just in case. Took her home and my beautiful girl died overnight.
Was there anything else I should have done?