Nutridrench also has iron. Is her neck completely limp? Could she have eaten something in the yard that was toxic, such as something dead or in a compost bed? Have you ever had any unexplained deaths or signs of lameness or Mareks disease in your flock? Hopefully, this is just due to dehydration and anemia. You can also learn tube feeding, which can be a safer and faster way of giving fluids and food. Here are the ingredients of Poultry NutriDrench:
https://www.drugs.com/vet/poultry-nutri-drench.html
https://www.drugs.com/vet/poultry-nutri-drench.html