Blood marks around coop?

[Lucy4]

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?

 

[Lucy4]

Update. Ok, upon closer examination of one of my orps, I can see there are dried drops of blood on her comb and inside one of her nostrils. And one of my brown eggs (so, from an orp) has two drops of blood on it. However, it looks like they dripped down... maybe from her face (rather than a crop injury.)

Since there's dried blood on her face, should I wash it? I've heard once there's blood around, they don't leave her alone. I'm just afraid of hurting her and if someone knows how to do this, please let me know. Thanks for tolerating my ignorance!