Someone asked me to weigh in on this thread. The only things I can think of other than she is hot is why she's hot. Perhaps she is having a hard time breathing due to her heart pounding. I lost a point of lay pullet to a heart defect. She was about 23 weeks old, had not laid her first egg. Found her sitting under the roost, so I picked her up and put her in a nest, thinking she may be ready to lay. She was panting and I realized it was becasue her heart was racing, visibly pounding in her chest. We took her inside and sat with her, no signs of anything wrong except her racing heart. So we put her back in the coop. The next morning, she came out with the others so we went to town. Two hours later when we got home, I found her just inside the coop door, apparently just then deceased with blood in her mouth. We did open her up and found her chest cavity was filled with that dark arterial type blood and one chamber of her heart had collapsed. I would not be surprised if your girl has a heart defect. She seems a big young to lay, but stranger things have happened. So, if that is what is wrong, there really isn't much you can do except keep her cool and unstressed. Nothing dietary will do anything for something like that.