Mine have just begun to moult and were slower for a couple of days before the moult started , could yours be on the verge of a moult ?
Have you heard any sneezing or sign of respiratory problems ?
There can be many reasons for hens to appear lethargic and until they become apparent I would probably just try giving them a boost to their systems with extra protein such as meal worms or live maggots, even oily fish like tuna can help.
Apple cider vinegar is beneficial in their water and if you do observe a moult then adding poultry spice to the feed also helps the hens.
As for the strange thing the hen passed , it may well have been what is known as a lash , which is discarded reproductive tissue , the hen can be a bit down before this is passed but usually picks up, however they don't always go back to laying again especially if the hen is a bit older.