Okay, the past couple of days I noticed that one of my hens (4.5 months old) was sitting down alot in the run while the others were moving all over the pen. Today, I watched her for a while cause I noticed her sitting down on the ground while eating some cracked corn. When she got up, she was walking carefully as if she was unbalanced or something. When she got over to some greenery, she sit down next to it to eat. She got up, got a little water then walked over and sit down. That is when I freaked out - she sit all the way down and her right leg was extended flat out on the ground in front of her, as if it was broken. But, she can still walk on it, occasionally stepping on her foot with the other foot. What the heck is wrong?? Also, does this sound like something that warrants her being separated from the others (for their safety)?