Whenever a new chicken is added to an existing flock, the risk of introducing or spreading disease and parasites increases. There is also an increased chance of injury or even death caused by squabbling as the new pecking order is sorted.
Quarantining New Chickens
One of the best ways to protect your chickens is to quarantine any and all new birds for a period of eight weeks before introducing them to your existing flock. New birds should be housed as far away from your existing flock as possible. Watch your new chickens closely for signs of illness or parasitic infestation and, if necessary, treat them accordingly. It is also important to use different equipment in the quarantine pen and to disinfect your footwear before visiting each group of chickens.
Establishing the New Pecking Order
Every time a bird is added to or removed from a flock, the pecking order changes. (Hence the saying start from scratch!) Within the first few days of owning your new chickens, you can expect some fighting: as they sort out the new pecking order. Do not interfere with this unless a bird is bleeding or injured. Once all of your chickens have found their new place, within the pecking order, this squabbling will cease. Sometimes the pecking order can take a few weeks to settle but this is unusual and advice should be sought, especially if one hen is bullying the others.
If you can move all of the chickens, new and old, into a new coop and run there is likely to be less fighting. You can also lessen the chance of serious injury by placing the new birds near to your existing flock in a separate coop/run area for a few days. After this short period you can introduce the new birds into your existing coop once your ‘old’ birds have gone to roost.