Introducing a new chicken

[wiill]

We have a Lavender Araucana and are thinking about adding another chicken to increase egg production (and potentially keep her company).
First a little background.
We have had the Araucana for almost a year now. We live in an area that has a lot of bush around and large sections and she appeared out of the bush on our property one day. We took to feeding her some scraps and eventually pellets and she kept on coming back during the day, but retiring into the bush at night and would perch in one of the nearby trees to sleep.
As time has gone on we have set up a small (open) hutch for her so that she would lay her eggs (beautiful blue-tinged shells) in one place (she finally took to it), but we have never attempted to put her in an enclosure - she is the epitome of free range, and wanders around the property hunting out worms in the lawns and gardens.
My questions are:
Is it wise to introduce another chicken given how independent the current one appears to be?
If so, should it be the same breed or a different type? Does it matter?
How old should the new chicken be? A chick? Older?

The last thing we want to do is create a situation where neither chickens are happy.

Thanks in advance.

 

[JerseyGiantfolk]

I've introduced chickens into the flock before, I kept the new ones in a cage inside the "real coop" with food and water until a month later I let them out to see the original chicken. They'd peck each other for a few, because they were establishing pecking order. I wouldn't get chicks because you'd have to set up the brooder and all (in my opinion I wouldn't get chicks) But you really don't need the same breed.
The OEG's I introduced got along well with my Japanese hen and Cochin roo.