One of our hens started acting strange yesterday - spending too much time in a nest box, not responsive to handling, not eating. We isolated her in the garage in a dog crate, where she would stand very still, fluffed up, and clearly straining/contracting (but not doing the penguin stance - just regular standing but fluffed up and tail level/down). We did some reading, then gave her a warm bath, some liquid calcium, and some nutri-drench. We left her in the dog crate overnight, and she passed a very watery, clear stool before bed. Woke up this morning and she had passed a very strange, soft, collapsed shell, and I found the yolk at the back of her crate, separate from the shell. She had eaten some of the soft egg thing and yolk, so I can't be sure whether it came out whole or already broken. She scarfed down some scrambled egg and pellets and drank a bunch of water, and is overall acting much more normal and active this morning. So now I'm wondering what happened, and whether we need to treat her with anything else. This particular chicken is the smallest of the group with a very small comb, so this could be her first egg. We also gave them a large pumpkin recently, so possibly she was calcium deficient. Or she could have a reproductive issue, and possible infection. And if she doesn't now, then she could begin one if that egg broke inside her. I guess the primary question is - should I start a round of prophylactic antibiotics? Or just monitor her for a while and see how she does? If I should do antibiotics, what kind - oxytetracycline, metronidazole, etc.? Is there anything else we should be giving?