Feed lacking protein and other nutrients, particularly Methionine, will also cause birds to pick feathers. Make sure you feed a diet balanced appropriately for the age and types of fowl you are raising. Mixing different ages of fowl or fowl with different traits promotes pecking by disrupting the flocks normal pecking order. Never brood different species of birds together. Don't brood feathered leg fowl, crested fowl or bearded fowl with fowl without these traits.
Curiosity can also start pecking.
When you change over to larger feeders and waterers it is helpful to leave the smaller equipment in the pen for a few days to help during the change. Also, allow 1 nest for every 5 hens. Vent pecking by layers is also a common problem. Once pecking starts it can quickly develop into a vicious habit. Most cannibalism occurs during father growth in young fowl.