Small hen ate hair
Try to pull it out, and check carefully that it is not wrapped around her tongue. There have been cases of losing a tongue from a hair or a string cutting off circulation. If her tongue is swollen or blue, just assume it is wrapped around it. I would be tempted to cut the hair off it you can't pull it out of the throat. Then I would give a few drops of castor oil or molasses to stimulate digestion and hopefully passing of some droppings.