Yeah not sure what else to suggest at this point. The protein is good, but just seems that maybe space and/or boredom are an issue. Sorry I can't think of what else to do.
If you know which birds are the ones causing the damage it'd be ideal to separate those out, but if they're all doing it to each other then that's going to be much more difficult.
Do you happen to know the protein % in your feed that the chicks are eating? Is that information available on your...
Do you know what breeds these are, or are they just "backyard mixes" with no specific breed?
I think maybe crowding are a factor here too, though it's hard to tell just how big each cage is and how many birds are in each one specifically by looking, but if they don't have space and things to...
Hmm what breeds are these chicks, do you know? It almost sounds like you have game birds or some other breed that's more fight prone.
Can you post photos of your set up? Or at least a very detailed description of your set ups with measurements (including brooder, coop(s), run). Crowding...
Not sure if you can get red colored heat bulbs, but the red color is supposed to help mask the color of blood which might help in this case.
Otherwise if the bully persists in picking on the others, I would separate it (but keep it in eyesight of the others, so another cage next to the first or...