Hi Nikki-
Just a couple of questions.....Could they be overcrowded? It is recommended that you have 4 sq feet per chicken. Another thing is, what are you feeding them. Chickens that need more protein will start pecking and eating feathers. That's because feathers are made of mostly protein. So if you're feeding them an age appropriate food, like chick grower or layer feed if you have hens, then that shouldn't be a problem.
Also another thing is, have you checked them to make sure they don't have any parasites? Lice or Mites can cause chickens to really "go nuts" and just pull their own feathers out. And feather mites eat feathers.
Another thing could be sheer boredom. If a chicken doesn't have anything interesting to peck around in, and they're cooped up in a small chicken coop or chicken run, then this can cause them to peck eachother. You could add some interesting things to their coop to keep them busy like a flock block, which is like a huge block of seeds--kind of looks like a giant parrot treat....., or you can hang a cabbage in there for them....
Good luck and I hope you figure out what's causing all the pecking,
Sharon