How does her lower belly feel? Does it feel full like it might be swollen from tissue or fluid? The downturned tail, problems walking, and using wings to balance can be a really bad sign. I lost a hen just last week who was showing that. When I did a necropsy, I found she had a pint of amber fluid in her lower abdomen from ascites. That can occur from egg yolk peritonitis, or heart or liver failure.
Keep her near her food and water in a basket or a dog crate. Feel inside her vent an inch or two with one finger, to check for a stuck egg. Shell-less eggs can be harder to pass than hard ones. But I wonder if she has something more serious than egg binding. Can you tell if either leg seems paralyzed?Was she vaccinated for Mareks disease?