My just over a year old Australorp may have an impacted/sour crop. She was acting fine and dandy this morning. She was running and scratching around with her usual intensity. I took a small bowl of plain yogurt outside, as I do very often, and let them at it (I only have two hens right now). I came back outside about an hour or so later, to find Miss Marple, the hen in question, standing and not moving. I've seen these symptoms before, in a hen who recently died of ours. I went over to her, she didn't move a muscle, I felt her crop and sure enough it was large (like a very large lime) and squishy. I thought it could just be the yogurt, but her behavior is all off. She just stands there and sleeps. Because of our last hen, I flew into action and have her safely inside with some grit and water. She is on a make shift roost I made and is sleeping away. Can this happen suddenly when too much yogurt is consumed, or suddenly in general? She's the boss out there and I wouldn't be surprised if she ate the whole thing (maybe about a 1/3 cups worth). I was thinking of vomiting her in the morning if she is in the same condition. I have never done that, but after my last hen passed I would try anything to make her better! Any ideas? What should my next steps be? Thank you SO much for the guidance!