On Wednesday my 2 year old hybrid laid a shelless egg. I started giving her calcium plus Vitamin D tablets daily from then on. She lay in the nest box on Friday, but nothing happened. She has been eating and drinking fine, although last night before retiring to the coop she was puffed up and somewhat lethargic. I noticed this morning she had done a rather large goopy poop, if thats the right word. She was her normal self this morning, doing what chickens do. I saw her on the camera in the nest box later and she was making some very high pitched noises, more vocal than usual when laying I went to check on her when I guessed she'd finished and found what I can only describe as a soft spongy ball on a string, which I have attached an image of. I pierced it qnd it was full of if clear liquid. She came out of the nest box and went about her business as normal. She seemed absolutely fine. After about ten minutes, she returned back to the nest box, where she currently is. Any idea what's going on, and what to do?