And you should try rubing in long strokes down from the throat to her chest incase there is something stuck in her food pipe?
When you say gullet are you talking about her crop?
Can you read about impacted crop and see if that has same symptoms?
If no poop, then she needs more nutrition. If you are willing, look up post on tube feeding. It's not that hard one you get over fear of hurting bird.
I would start with 10 cc of pedialyte or Gatorade. Wait an hour and do it again.
Good luck and let's us know how it turns out. Good or bad that is how we learn from each other's experiences.
If you squeeze her crop and get close to her mouth, do you smell anything? Book City Chicks says to hold her upside down and see if gravity helps Hold her by legs with one hand and massage crop with the other. Sour crop is squishy crop
Impacted crop is hard. Teaspoon of olive or mineral oil may help move the impact. Feed her that and then massage.
But I do t know how she is having diarrhea with crop problems. It also concerns me that you had another one die. If she doesn't make it, you may want to consider a necropsy