I just lost my 2 year old Rhode Island Red…sounds like she is egg bound😟 Your girl is showing typical symptoms…tail down, sitting, not very mobile. There is good advice on Egg Bound issues on this channel…magnesium (Epsom salt baths several times a day)
Check the vent…have lubricant)…I used...
New member here, Amish Chick, and excited about our new backyard adventure! 5 Rhode Island Reds pullets arrive from a local organic farm in a few days!