BEN SOUTH SAYS: Once flocks are established, a pecking order will have been formed and it is maintained by dominant birds within the flock. This is completely natural behaviour, but it may lead to injuries if the birds cannot agree to a hierarchy.
When new birds are introduced there is often a period of time while the hens are reorganising this dominance. Aggression can be particularly bad if the hens you bring in were dominant in their last flock and this can lead to trauma and high levels of feather pecking.
It is more favourable to keep the flock as stable as possible by not introducing large numbers of birds at once or removing them. It’s a good idea to introduce or remove birds, say for treatment, in pairs so as to avoid an individual animal being displaced. If you’re looking to introduce several birds at once then it’s best to introduce them on neutral ground, somewhere new where neither flocks have been before. The addition of a cockerel can be beneficial in controlling aggression. If it’s one bird that is causing the issue, then often this behaviour becomes a habit and that bird may need to be removed from the flock for a period of time before being reintroduced. It can be beneficial to isolate the hen in her own penned area so that she can still see and be a part of the flock, but cannot come into contact with them.
Behavioural traits, such as aggression, must be stopped as soon as possible as they can often become ingrained into the flock and lead to high levels of feather loss or trauma. Using pecking aids such as blocks or Lucerne bales can be useful. It is important to ensure that the birds can peck for a reward so that they don’t get bored of the object.
If the hens have only just been introduced then ensure that there is adequate feed, water and roosting space so that the birds can get away from each and avoid competitionfor resources. Over time, the pecking order will be resumed and the feather loss will recover. It would be prudent to introduce a multi-vitamin into the water during this time to help to deal with the raised stress levels.