There are smears of blood on the sides of my waterer, feeder, and nesting box. I looked at the chickens and I can't see any injuries. The only thing I could think of was that it's inside one of their beaks/mouths. What could have happened? It's not a huge amount of blood but it's certainly spread out. It's not like I can get them to open wide so I can see in there. Not sure what to do?