Chicken sick? showing behaviors that she never done before.

[blackwingedwolf]

One of my new layers have been acting very strange. During the night about four days ago, she laid an oops-egg and she hasn't been acting like herself since then and she hasn't laid any more eggs (she laid her first five continuously before the oops-egg). The first thing I noticed was that she wasn't eating as she used to. She was always the first one in the food bowl, but now, she walks past it and drinks water or lays down and watches the other five as the eat. Every time I'm out and see her go poop, I notice it's really watery, and one time, I noticed it was a strange yellow. She's been walking off by herself many times and been staying out longer than the other chickens when they already headed to bed. She was always the firstto do everything and was always with the other chick that we got with her. If you know what's wrong, please help me and if you need more info, I'll be more than happy to answer any questions. I'm really worried about her.