Is the side of your brooder reflective? I've noticed chicks will peck at their reflections. I had one quail do it neurotically, and I had to cover the wall to get her to chill out.
I would need to see a picture to verify, but what you're describing sounds like what I encountered with a roo who wasn't sure what he was doing and wasn't very gentle with the hens. He was pecking their ears specifically (I think trying to make them squat for him), and the blood hardened into a...
I second the Black Soldier Fly ID. Good bugs! The larvae are sold as treats for poultry and they're voracious, so they shred through compost in a hurry. The adults don't actually have the ability to eat and don't tend to become house pests like other flies. Plus, they're very pretty insects...
I tried introducing the 10 day olds to my DIY no-waste feeders and... apparently the experience of pooping in their food was just too decadent to give up. Might need to make one with smaller head holes.
I've had great luck with using 1 gallon distilled water jugs. Just cut the top off above the handle so you can fill it and make little rectangular holes in the sides for them to stick their heads in. Basically zero waste.
The jugs are too big for the chicks, though, so for the first three weeks...