I have ten five week old pullets in a homemade brooder that's 5 feet long, 3 feet high, and 3 feet wide. The floor is 1/2 inch hardware cloth, and I've put in two pieces of wood, sized about 2 feet by 6 inches, to give them a place to stand if they want to get off the mesh. They are being fed non-medicated chick starter, and are unvaccinated chicks from Cackle Hatchery. The breeds are: doms, SLW, EE, BA, LB. I hung up 3 pieces of dry bread and several little shiny silver things from their ceiling to give them something more interesting to peck at, and they don't seem interested. The temp in the brooder is around 80. I have slowly decreased the heat over the past few weeks and have just this morning decided to shut off the heat lamps in there during the day as the brooder sits in sunshine and heats itself up. So, that's all the info I can think of help you chicken pros out there know what might be going wrong here. They are being pecked until they're bloody and it's just awful. I'd welcome advice.
One of the odd things about chickens is that they will keep picking and picking at a wound on another bird. You really need to separate the injured ones from the others as soon as possible...and keep the injured ones apart, too. Don't put them back together until they are healed or the injuries will just get worse due to additional picking. There are some blinders/peepers that you can put on their beaks to stop the picking as they get older. Do a search for "peepers" on the forum, and you'll find some ideas. Peepers aren't the only solution; just one of many things you can try.
Cutting off the heat was a good idea. Try reducing the temperature to where you have around 65 to 70 degrees at the max. They should be pretty close to fully feathered out so they should not need much heat, if any. Too much heat can contribute to cannibalism. Watch them to see how they react to the heat reduction and adjust as necessary. A red light is always a good idea. It seems to calm them down anyway, but when their feathers are coming in, the quills are sometimes blood-filled and red. They may be picking at that red color. The red light makes it hard to see the red. You should have plenty of room for chicks that age. These two are my best guesses.
I have to say I really don't like the idea of wire mesh bottoms. My chickens spend 90% of their time scratching around for food or whatever. They would much rather scratch for their dinner than eat out of a feeder. Even with some "toys", I bet your chicks are bored. Try putting in a tray of sand or shavings with some scratch mixed in, so they have something to mess with all day instead of each other.
