Don't throw in the towel quite yet. I hatched 23 chicks and most of them will be a week old on March 30th so I don't have this problem so much yet. But, I do have two turkey chicks in with them... One is large enough to fly a little so she's pretty big. No problems with pecking from her so far. My little turkey chick is the one that pecks - at my larger turkey chick; I think she is jealous that the larger one can fly...
My husband and I are newbies. My chicks do peck at each other from time to time. To counter this behavior and nip it in the bud, we have a large cardboard brooder that takes up a good quarter of our spare room and we can enlarge it if need be; the coup is 5 x 8 and almost finished. I'm finding the large brooder is preventing a lot of this nasty pecking behavior as they get older. They seem to start this 'picking on each other' pretty early if they are too cramped or just plain bored! Yesterday I went across the road and picked out a good sized branch of a tree, loped off the extra branches and blunted anything sticking out. My husband then secured in in the cardboard brooder by putting the ends through the cardboard. I have a wide 2 x 4 they hop up on and over; I carved out a good sized piece of grass from the back of the lawn, put it into a low bowl and put that in. All of which greatly attracts their attention as something to play with, I have two branches, one on the floor of the brooder and one a little higher, as my chicks are quite tiny yet. Just to make a little challenge for them. Not a week old yet and starting to feather out!!
I am also finding that if they are bored with their food, they will supplement it by pecking at each other. To that end, I give them treats that don't need grit. I make plain, unsweetened yogurt in my hova-bator overnight: 8 to 12 cups raw, whole milk, add 3 tbsp store bought plain, unsweetened yogurt, put into bator for 6 hours at a temperature of about 100F! They love the yogurt and it gives them bacteria they need. I had to make a chick feed slurry for one chick that wasn't eating and the rest love that too. Give them a special treat of egg yolks with a little egg white mixed in - they will re-invent football when you do this, they love it so much.
I try to stimulate them as much as I can and handle them a little more to make them calmer and more friendly. Maybe that is all this mean, pecker really needs. They can become jealous... and that one is obviously wanting attention. Hope this helps some and update as to what happens.
Stephanie