Chicken suddenly lethargic, not eating, mouth open, yellow water-poop, Please Help!

[D Uccle Uncle]

If she's egg-bound she needs immediate treatment.

I don't think use of a mister is related to her current condition (I have and use one) whereas dietary changes might be.

 

[Eggcessive]

If egg bound is suspected, give human calcium with vitamin D 300 mg to 600 mg orally once. Pictures of the hen and droppings may help.