When I went out this morning to release the girls I noticed after they had all scrambled away that there was blood on the upper perch. It was dry but had been a good bleed judging by the rivulets and drip points. I scooped out under the spot and got a large cat litter scoop of bloodied pine bedding. No disturbed feathers nearby so I don't think someone got a blood feather pulled out. So I spent about an hour watching them, looking for obvious vent bleeding or other injuries. Combs look good, legs and feet seem fine. I really can't figure it out. I just put 3 young pullets into the general population 2 days ago. They have been quarantined for 3 weeks. There is some bickering going on with the new pecking order being established. I'm hoping it doesn't happen again but worry about disease of course.