One of my hens was sitting in her nesting box much longer than usual today, when I pulled her out, it looked like a clear watery substance had came from her vent. She's walking really slow with the feathers around her vent open like she's going to poop but her vent is closed. Her vent looks normal, no redness and no feathers missing. She did "poop" once and it was watery with bubbles and a little whitish color. Her feathers below her vent have a whitish mucous on them. What could this be?? She's very uncomfortable and I don't know how to help.