The microscopic cooties that cause cocci are everywhere. Diarrhoea, looks generally unwell, not eating, gasping for breath if severe. After she is dried off, the vent should be inspected. Do not use powdered milk as it is without whey, a necessary element. I am also building an addition to my coop soon so that some of the run is in the sunlight, seeing that the rest in usually damp because it is under trees.
January 19, 5:
Basic Chicken First Aid
If the hen looks well, she may just have eaten lots of green foods. Straining - see Egg Bound, Egg Peritonitis. The wings out and tail down does sound like she is straining to pass something. Notify of new replies to this comment - off. Monitor the skin and feather health of birds routinely for external parasites.