Hello! I've also seen people do molasses flush, for my hen Ginger she was in our basement, I had an area where I covered the floor with thick cardboard. I could see the straw coming out every day because her poo was very watery.
Hello! I had a hen that had something similar a year ago, I had her inside and she basically ate watermelon for a month, she lost weight but she also expelled the straw she ate. I'm sorry for your hen!