Hen bleeding internally! Help?

[FreeChicken!]

One of my three-year-old White Leghorns just suddenly started bleeding today--not sure what time; only just noticed now. The feathers all over her backside are bloody, and it really alarmed me. I tried to clean her up as best I could. She still seems energetic and excitable--no unusual behavior. Yesterday she was acting a little oddly--making a strange noise occasionally and being unusually calm--but she's normal today. The blood is kind of freaking me out though.
What is this? Should I be worried?

 

[nettifer]

they do every nowand then pass intestinal lining which can look like blood clots keep an eye on her as long as she seems well dont worry too much

 

[FreeChicken!]

Okay, thank you!