Going to need more details please, but essentially seperate especially if they are hurt, give them more space, things to hide behind, treats to divert their attention, also make sure they have enough quality feed. Imp
Cannibalism is due to your chicks being bored! Try a few of these things and see if they don't help: Dust Baths: Get a small box or cat litter box and fill it w/ sand .. your chicks will have tons of fun dusting themselves .. plus it'll help keep them happy! Fresh Greens: Fresh Greens, such as grass, cabbage or just about anything. Or you can hang toys in their brooder to help prevent boredom.
Depends on what age of chickens we are talking about, what gender in some cases, what feed they are getting including treats, and your individual setup. It could be over crowding, too low of protein from feed that isn't age appropriate or too many treats, not enough feed (chickens should be able to eat 24/7 on something), confined space with nothing to do, too many roosters, or it could start with pecking an odd feather or toes with chicks and then moving on to doing more damage. Each of those problems has a different solution which also depends on age.
