Last week our pretty little Blackstar (about a year old, has been through one molting), who has been a decent layer, sat on the nest for hours for at least two days in a row and never produced an egg. By Friday, she was trying to pass what I believe was an undeveloped egg. She couldn't get it out herself. It hung from her vent. Eventually I put on gloves and tugged the rest out and washed her. She has drunk water, but we haven't seen her eating since. Her stool is liquid-y and messy we bathed her underside again yesterday. She's listless and getting thinner by the day. We've presented her with laying crumbles, crushed oyster shells and Tums, clover and other greens (usually her favorites), and she doesn't eat. She looks dazed and moves slowly. This is only the 4th hen we've ever had, and I've never experienced anything like this. Can anyone offer advice? Thanks so much.