Adding new chicken to existing flock?

The best thing I've found is to separate the coop with wire so they can look but not touch, unless one chicken sticks its' head through the wire onto the other side. That way they can see each other and, sometimes, come into contact...but no vicious attacking can happen.

After about 4 days of this, let them free-range somewhere, on neutral territory. Be there to watch over events, and any time a serious fight breaks out make a loud noise, or spray them with water, or throw treats to distract them. Keep it short, and then over the next few days extend the amount of time.

Finally just leave them out together. Let any fighting happen, providing it's not really brutal. The squabbling needs to happen so they can sort out the pecking order. Make sure there's plenty of food and water around, and spend as long as possible with them so you can be sure they aren't being too aggressive. Throw treats if it's getting too serious. As long as there is no blood, that's fine - if there is blood, you need to separate the newby hen again. Let them go to bed together, keep the house locked so you can be there to release them the next morning. There will be fighting but it should settle within a few days, although the hen at the bottom of the pecking order will always be more 'hen pecked' than the others.

Hope this helps, I know how horrible it can be introducing a new hen to a flock!

When we indtoduce new chickens we always introduce at least two at a time. Seperate the enclosure into two parts, one for the existing flock and one for the new. Make sure you use wire mesh or similar, because the aim of this is that the chickens get used to each other without being close enough to attack each other. Keep them this way for a week or so, they put them together. If your still having problems, seperate them at night.