All types of birds peck at each other. They use this as a method of displaying dominance or developing social order. However, uncontrolled pecking can lead to serious injuries and even cannibalism, when ducks are in close confinement with each other. The behaviour may develop because of boredom, nutrient deficiency or stress caused by environmental factors, such as high temperature, low humidity or poor ventilation in the ducks' living areas.
Avoid keeping too many ducks together. The more crowded the birds are, the more likely they are to begin pecking each other.
Ensure all the ducks are receiving enough food and water, without having to compete with each other. Check that the food contains sufficient protein and sodium, and that the ducks find it palatable.
Keep light intensity low inside the duck shed, even changing the bulb to one emitting a red hue. Additionally, ensure that the temperature is comfortable and that the enclosure is well-ventilated.
Check the ducks for parasites and other diseases. Parasites can make birds irritable, causing them to peck at each other. Remove weak and unhealthy ducks from the group, as they are likely targets for the other birds.