Signs of injurious pecking
Inspect the birds regularly and look closely at their behaviour. Note instances where one bird directs pecks towards the body feathers of another, particularly around the base of the tail. This is often done repeatedly and results in a feather or feathers being removed and sometimes eaten by the culprit bird. It is good practice to sit or stand and observe an area of the house for five or ten minutes. This will allow the birds to settle and will increase your chance of spotting any injurious pecking behaviour that might be occurring in your flock.
Plumage damage is another good indicator, although it is difficult to spot in the early stages of injurious pecking. However regularly monitoring feather cover in your flock can help spot injurious pecking as soon as possible. Look for feather damage around the back and base of the tail; this is where severe feather pecking often starts. Pick up some birds and check under the outermost feathers for any signs of baldness, particularly around the base of the tail. Look at the tail itself, the downy feathers on the sides can often be removed which make the tail lose its fullness. Also listen to the flock and see if you can hear any characteristic ‘squawks’ which could be from a victim of a severe feather pecker. More details on how to monitor feather cover can be found following the links below.